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The threatened Pecos Bluntnose Shiner, Notropis simus pecosensis, is restricted to a 333-km segment of the Pecos River, New Mexico. This is a relatively long, undammed segment, but the flow regime is highly modified and the river channel is degraded. Within the occupied segment, upstream river sections are less-degraded with a wider river channel and shifting-sand substrata, whereas downstream river sections have increasingly narrow river channels and compacted, silt-sand substrata. We studied the longitudinal distribution, length-structure, and population status of N. s. pecosensis from 1992 through 2005. On average, individuals were larger upstream and smaller downstream. Highest densities were in upper-middle portions of the study area. Infrequent high-density collections from lower river sections included only small juveniles that were displaced from upstream. In contrast, high-density collections from upper-middle river sections included all life stages. Thus, we concluded that the core population was restricted to upstream river sections. These river sections have relatively diverse habitat when streamflow is perennial, but are largely desiccated during streamflow intermittence. The core population of N. s. pecosensis was evenly distributed between 1992 and 2000, when streamflow was perennial, but became patchily distributed among refugial habitats between 2001 and 2003, in response to low discharge and periodic streamflow intermittence. High density collections resulted from the concentration of fish in refugia. However, N. s. pecosensis percent species composition declined during this period, indicating that refugia were unsuitable. Low density collections observed after perennial streamflow was restored in 2005 indicated a population collapse between 2001 and 2005. Streamflow intermittence is a threat to the core population of N. s. pecosensis, but habitat degradation appears to limit its distribution. Thus, channel restoration and perennial base-flow will both be important for conservation and recovery.
We investigated the effects of artificial incubation regimes, experimental temperature, and age on the locomotor performance of New Zealand's only endemic oviparous lizard, Oligosoma suteri. Artificial incubation is often used to produce founders of new populations of endangered reptiles and can have significant effect on juvenile phenotype. Eggs of O. suteri were randomly distributed among three incubation temperatures (18, 22, 26°C). Juvenile (n = 117) maximum sprint speed was measured over three trials at 18, 22, and 26°C, and at one and four months of age, and behaviors during sprinting trials recorded. Sprint speed increased with an increase in experimental temperature and age. After removing the effect of individual size, juveniles incubated at low temperatures (18°C) were slower and exhibited locomotor behaviors likely to be detrimental for their survival (running towards stimulus). Individuals were consistently fast (or slow) at any given age or experimental temperature. Our data suggest that O. suteri incubated at warmer temperatures may have higher survival when released to the wild.
To investigate the role of ecological and historical factors in the organization of communities, we describe the ecomorphological structure of an assemblage of snakes (61 species in six families) in the Cerrado (a savanna-like grassland) of Distrito Federal, Brazil. These snakes vary in habits, with some being fossorial, cryptozoic, terrestrial, semi-aquatic, or arboreal. Periods of activity also vary. A multivariate analysis identified distinct morphological groups associated with patterns of resource use. We report higher niche diversification compared to snakes in the Caatinga (a semi-arid region in northeastern Brazil), with fossorial and cryptozoic species occupying morphological space that is not occupied in the Caatinga. Monte Carlo permutations from canonical phylogenetic ordination revealed a significant phylogenetic effect on morphology for Colubridae, Colubrinae, Viperidae, Elapidae, and Boidae indicating that morphological divergence occurred in the distant past. We conclude that phylogeny is the most important factor determining structure of this Neotropical assemblage. Nevertheless, our results also suggest a strong ecological component characterizes a peculiar snake fauna.
Sexual dimorphism is widespread among vertebrates, and may be attributable to sexual selection, differences in ecology between the sexes, or both. The large aquatic salamander, Amphiuma tridactylum, has been suggested to have male biased sexual dimorphism that is attributable to male–male combat, although detailed evidence is lacking. To test this, data were collected on A. tridactylum head and body size, as well as on bite-marks inflicted by conspecifics. Amphiuma tridactylum is sexually dimorphic in several characters. There was no sex difference in body length, but males had heavier bodies than females of the same body length. Larger males had wider and longer heads than larger females, but whether any of these sexually dimorphic characters are attributable to differences in diet is unknown because diet data (by sex) are lacking. There was no difference in the number of bite-marks between males and females, and juveniles also possessed bite-marks, suggesting that the biting is not necessarily related to courtship or other reproductive activities. In addition, fresh bite-marks were present on individuals during months well outside of the breeding season. Biting was observed in the field and lab to occur by both sexes on both sexes, during feeding-frenzy type foraging. Thus, biting is likely related to foraging rather than to courtship. The sexually dimorphic characters remain unexplained, pending sex-specific diet data, but there is no evidence that they are related to male–male combat or to courtship.
During the examination of Lake Tanganyikan fishes held at the American Museum of Natural History, several specimens of the genus Chrysichthys could not be identified to any of the known species from the lake or elsewhere. This material is believed to represent a new species, distinguished from other species of Chrysichthys on the basis of a weakly expressed or absent postcleithral process, 14–16 rakers on the first gill arch, toothplates of the premaxillae and palate bearing small and tightly packed teeth, vomerine toothplates widely separated and narrower than those on the pterygoids, supraoccipital broad and contacting the predorsal plate, body width at pectoral-fin insertions 4.9–5.3 (5.1 ± 0.1) times in SL, interorbital width contained 3.0–4.1 (3.4 ± 0.4) times in HL, distance between posterior nares contained 4.0–4.8 (4.3 ± 0.3) times in HL, maxillary barbels contained 4.1–5.5 (4.7 ± 0.8) times in SL, and the distance between posterior margins of adipose fin and hypural plate contained 5.1–6.0 (5.5 ± 0.3) times in SL.
In animals that display acoustically, males may use the presence of conspecifics to choose optimal times for display, and in doing so minimize costs of advertisement while maximizing the probability of mating success. Among anuran amphibians, it is well known that males can adjust their calling behavior in response to fluctuating social conditions. Within a species, it is not known whether males adjust their calling activity differently in response to females, and the immediate chance of mating, than in response to males, and the risk of competition for mates. In the Australian toadlet Pseudophryne bibronii, males construct terrestrial nests and call to advertise territory occupation and to attract potential mates. In this study, I presented either males or females to nesting males and found that male call type, and aspects of call structure, are influenced by the sex presented. More importantly, I found that males called at a significantly higher rate in response to females than in response to males. These results suggest that nesting male toadlets strategically adjust calling behavior according to contingent chances of male–male competition and mate attraction. These findings are unique because they indicate that males do not advertise maximally until there is an immediate chance of mating success.
Spawning site selection can strongly influence egg survival and the distribution patterns of species. Coastal areas are risky environments for breeding amphibians because the rate of egg survival falls drastically with increased salinity. The working hypothesis of the present study was that Buergeria japonica, a racophorid anuran inhabiting beach in coastal areas, avoids spawning sites with high salinity. I tested whether females of B. japonica select oviposition sites based on salinity levels. Amplexed pairs were collected in the field and introduced into a container with dishes as potential spawning sites, two with pure water and two with water of various salinities. With one exception, females laid significantly more eggs in pure water than in salinities greater than 1‰. Female B. japonica have an ability to distinguish salinity levels when laying eggs. Spawning site selection based on salinity seems to be important for frog species distributing in coastal areas to reduce egg mortality.
Two new species of the formerly monotypic gobiesocid genus Discotrema are described. Discotrema monogrammum is described from specimens collected from crinoids in Papua New Guinea and Indonesia, with photographic and literature records from the Great Barrier Reef, Philippines, and Christmas Island, Indian Ocean. The specimens were first believed to be a color form of D. crinophilum, described from Fiji and Papua New Guinea, and also commensal in crinoids. Both species have a single, white or pale yellow lateral stripe, whereas D. crinophilum also has a mid-dorsal white stripe; unique mitochondrial DNA sequences showed that D. crinophilum and D. monogrammum are distinct lineages. Discotrema zonatum, which has irregular dark bars on the side of the body, is described from a single specimen from Fiji, apparently commensal on soft coral. The three species are also distinguished by pectoral-fin ray counts and three proportional measurements. Some authors have placed Lepadichthys lineatus in the genus Discotrema, but its disc morphology and other characters indicate that it should remain in Lepadichthys. A key to the species of Discotrema is provided.
Although infestation of turtle nests by dipteran larvae is known to occur in both freshwater and marine species around the globe, the role of insects in turtle nests remains unclear in this relatively understudied phenomenon. The present study was part of a larger effort to elucidate the role of dipterans in sea turtle nests at rookeries in Central Queensland, Australia; this portion of the study examined the factors that predispose nests to infestation. Physical and biological nest parameters were measured in relation to the number of infested eggs and hatchlings in individual sea turtle nests. Data collected during the 2003–2005 turtle nesting seasons were analyzed by multiple forward regression, as an analytical tool to explore dipteran infestation events. The most significant factor predisposing nests to infestation was the number of dead propagules present (dead eggs and dead hatchlings, combined), reinforcing the hypothesis that dipteran larvae are scavengers of necrotic material in affected nests. Other factors play secondary roles in determining a nest's propensity for infestation, including nest depth, clutch size, and cumulative rainfall in the weeks preceding hatching. This study furthers our understanding of dipteran scavenger species and discusses the potentially positive benefits their actions may impart to the beach ecosystem.
Rivulus planaltinus, new species, from the Maranhão River drainage, upper Tocantins River basin, central Brazil, is described. It is a member of a subclade of the subgenus Melanorivulus endemic to the central Brazilian plateau, which is diagnosed by having ventral process of angulo-articular vestigial and flank intense greenish blue or greenish golden, to purplish blue above anal-fin base in males. The new species differs from all other species of the subgenus Melanorivulus by the absence or extreme reduction of pelvic fins and pelvic girdle, numerous vomerine teeth, and a wide basihyal.
Rivulus planaltinus, sp. n., da drenagem do rio Maranhão, bacia do alto rio Tocantins, Brasil central, é descrita. Ela é um membro de um sub-clado do subgênero Melanorivulus endêmico do planalto central brasileiro, o qual é diagnosticado por possuir processo ventral de ângulo-articular vestigial e flanco azul esverdeado intenso ou dourado esverdeado, a azul arroxeado acima da base da nadadeira anal em machos. A nova espécie difere de todas as outras espécies do subgênero Melanorivulus pela ausência ou redução extrema de nadadeiras pélvicas e cintura pélvica, dentes de vomer numerosos, e um largo basial.
The body condition of an animal reflects its energetic state such that an animal in good condition has greater energy reserves than one that is in poor condition. Body condition in turn should be positively correlated with fitness because energetic reserves limit the amount of energy that can be allocated to reproduction. Using Spotted Turtles (Clemmys guttata) as a model system, and three years of field data from a South Carolina, USA population, we tested the prediction that reproductive output increases with maternal body condition. The effect of body condition on the reproductive output of female turtles was examined at three temporal scales (among clutches, among nesting seasons, and among females) using several variables including clutch frequency, clutch size, and multiple measures of egg size. We predicted that females in good condition will have a higher clutch frequency than those in poor condition; that females in good condition will have larger clutch sizes than those in poor condition; and that females in good condition will have larger eggs than those in poor condition. Among clutches and nesting seasons, we found no relationship between female body condition and reproductive output. Among females over the entirety of the three-year study, we found a positive relationship between body condition and clutch mass and egg size. In addition, females in poor condition and females in good condition both produced larger clutch sizes than females in intermediate condition. Our findings suggest that within a given reproductive bout and within a given reproductive season, energy reserves do not affect immediate reproductive investment. However, over the longer-term, females in good condition have greater reproductive output, which supports the idea of a bet-hedging life history strategy in turtles.
Nanobagrus immaculatus, a new species of bagrid catfish, is described from the Kahayan River drainage in southern Borneo. Nanobagrus immaculatus is most readily distinguished from congeners in having a uniformly dark-colored body lacking pale spots or patches (vs. pale spots or patches always present), larger eye (16.7–18.2% HL vs. 9.0–16.1), and a longer adipose-fin base (24.9–26.6% SL vs. 12.8–21.6). The synapomorphies used to diagnose Nanobagrus are reviewed and re-examined. Pseudomystus fuscus is hypothesized to be more closely related to Nanobagrus than to all other Pseudomystus and is hereby reassigned to the former genus.
The annual reproductive cycle of Creagrutus guanes (Teleostei, Characidae) was studied in a tropical mountain river, a type of habitat where reproductive biology of fishes has been scarcely investigated. Analysis was made on adults, 70 males and 135 females, which were captured in 13 monthly samplings. The analysis was based on macro- and microscopic observations of gonads, and on weight of gonads, mesenteric fat, and liver. Weight and microscopic observation of ovaries and testes, as well as macroscopic observation of ovaries, suggest reproductive activity was concentrated in periods of low rainfall. In males macroscopic observations did not reflect the maturity state revealed by histology. Fat reserves also showed a seasonal variation related with rainfall pattern. Given that dry season reproduction is relatively uncommon in tropical freshwater fishes, ultimate factors determining such a pattern are discussed.
Life histories of a species often vary geographically, and comparative studies of populations in different habitats are useful for understanding how environmental variation influences life history. Such studies are currently lacking for most snake species despite their growing importance as model organisms for life history studies. We present life history data for a population of Western Cottonmouths (Agkistrodon piscivorus leucostoma) inhabiting a “riffle–pool” creek system (Rocky Grove) located in the Ozark Mountains in northwest Arkansas and compare our results with those available for other populations. One hundred forty-two individual snakes were captured 283 times from August 1996 through September 2003. Mean snout–vent length (SVL) of adult Rocky Grove A. piscivorus (males 60.8 ± 2.68 cm, n = 47, females 54.9 ± 1.74 cm, n = 47) was among the smallest reported for any population of A. piscivorus. Rocky Grove A. piscivorus also exhibited a low degree of sexual size dimorphism (SSD) compared to other localities, and mean female SVL was 90.3% that of males. Growth rates were the slowest reported for any temperate zone pitviper (males 0.151 ± 0.053 cm/month, n = 46, females 0.178 ± 0.06 cm/month, n = 66). Limited data also indicate low reproductive output for this population in terms of frequency of reproduction and litter size. Female reproduction averaged less than biennial as evidenced by consistently low proportion of pregnant to non-pregnant females (18.4%) and reproductive histories of individual female snakes. Litter size averaged 4.1 ± 0.63 (n = 10). Mating at Rocky Grove occurs in late summer but may also occur in spring. Agkistrodon piscivorus at this study site may be limited in energy acquisition rates relative to the conspecifics in other parts of the range.
This study explored how historical and current hydrological conditions covaried with colonization and occupancy probabilities for 14 pond-breeding amphibians at 32 natural sinkhole ponds over a five-year period. Occupancy and colonization were estimated independently for breeding adults and juvenile recruits (metamorphs) of each species using proportion of area occupied (PAO) models that incorporated species detection probabilities. Model selection revealed whether historical or current hydrological conditions are more important in determining occupancy and colonization probabilities for each species. Adults and metamorphs of ranids and most salamanders had occupancy and colonization rates that were best estimated by models that incorporated each pond's historical hydrology. A comparison of colonization and occupancy dynamics for history dependent species indicates that these species contribute little to species turnover within local pond communities. Adult occupancy and colonization of hylid, bufonid, and a pelobatid species were more dependent on the immediate hydrology of a pond within a year. Recruitment dynamics of these same anuran species were best fit by models that incorporated both current and historical pond hydrology. In some years, these species had high probabilities of producing metamorphs in ponds where they had not produced metamorphs in the previous year. Increases or stability in colonization probabilities between years sometimes coincided with stable occupancy probabilities, indicating that these opportunistic species are responsible for species turnover in local communities. Short-term species turnover within local amphibian communities appears to be driven by these opportunistic species and linked to major changes in weather between consecutive years.
Eptatretus lopheliae, new species, is described from three specimens caught at 430–442 m depth in cold-water coral habitat off the southeastern United States. It is diagnosed by elongated tubular nostril, lack of nasal-sinus papillae, five pairs of gill pouches, 3-cusp multicusps in anterior and posterior row of teeth but with variation of 4 cusps in posterior row, 38–41 total cusp count, 19–21 prebranchial slime pores, 88–89 total pores, palatine tooth triangular, and pinkish-orange body color. Eptatretus lopheliae is a small hagfish species observed, videotaped, and caught in close association with Lophelia pertusa reef habitat.
Infectious diseases, including those caused by ranaviruses (family Iridoviridae), are among the suspected causes of global amphibian declines. Like many pathogens, ranaviruses appear to infect multiple species. We examined several North American amphibian ranavirus isolates to improve our understanding of the effects these viruses have on host communities. Our study had two objectives. The first was to characterize isolates from epizootics affecting wild amphibian populations and compare them to previously described isolates. The second was to test whether amphibian ranaviruses infect ecologically relevant heterologous species, and if so, document the outcome of exposure. The combined results of restriction endonuclease (RE) digestion analyses, sequence analyses, and experimental challenge trials suggest that two amphibian ranaviruses, Ambystoma tigrinum virus (ATV)-like viruses and Frog Virus 3 (FV3)-like viruses, are distinct viral species with different ecologies. Characterizations revealed that several isolates with identical major capsid protein (MCP) gene sequences have distinctive RE profiles. This suggests that high degrees of similarity in MCP sequences may belie important differences among isolates, and we argue it is imperative to characterize ranavirus isolates beyond sequencing the MCP gene. Results from experimental exposure trials indicate that multiple host species may be involved in the ecology of ATV- and FV3-like viruses, and that each virus is capable of infecting several amphibian species that share breeding habitats. Additionally, field collections revealed FV3-like ranaviruses circulating in Wood Frogs (Rana sylvatica) and ATV-like ranaviruses circulating in Tiger Salamanders (Ambystoma tigrinum diaboli) in the same week at a single breeding pond, highlighting the ecological potential for transmission among different host species. Our research also corroborates a growing body of knowledge that suggests individual host populations may differ in their responses to ranavirus infection, a finding with complex conservation implications. Ultimately, experiments elucidating the dynamics of intra- and inter-specific transmission will be particularly important for understanding the roles that ranaviruses play in their host communities and the threat they pose to amphibian populations.
We studied the ecology of Anolis nitens brasiliensis during late-dry and early-wet season 2005 in a Cerrado habitat in Tocantins state, Brazil. Most lizards were found on tree trunks or leaf litter in non-flooded igapó forest. Most were found in shade or filtered sun on both cloudy and sunny days. Body temperatures (Tbs) averaged 30.6°C and did not vary among microhabitats. Microhabitats exposed to direct sun consistently reached extremely high temperatures whereas microhabitats in shade or filtered sun provided temperatures throughout the day allowing lizard activity. Nineteen prey categories were found in lizard stomachs, but the diet was dominated by spiders, crickets/grasshoppers, ants, and beetles. Although lizards that ate large prey ate fewer prey, no correlation existed between size or number of prey and lizard body size (SVL). Males were larger in SVL and mass than females, and males had relatively longer hind limbs than females. Females were variable but larger in body width. In general, the ecology of Anolis n. brasiliensis is similar to that of its Amazonian relatives, with the exception that it lives in a more thermally extreme environment and is active at slightly higher Tbs. Ecological traits of this lizard, particularly its reliance on relatively low Tb for activity, suggest that it might be particularly vulnerable to local extinction if its habitat is altered. The presence and apparent widespread distribution of A. n. brasiliensis in the Cerrado provides further evidence that the “vanishing refuge” theory cannot account for geographical patterns of distribution in the A. nitens complex.
Lucania goodei and L. parva are close phylogenetic relatives that differ in abundance along a salinity gradient where L. goodei is found predominantly in freshwater sites, and L. parva is found most often in brackish water sites. It has been suggested that these taxa diverged along a salinity gradient. In order for selection to cause divergence, there must be local adaptation where each species does best in the environment in which it is most often found. In this paper, I test for local adaptation in L. goodei and L. parva during early life-history stages by raising eggs and larvae of each species at 0, 10, 20, and 30 ppt salinity, covering the gradient between fresh water and sea water found along the coast of the Gulf of Mexico. Salinity tolerance differed between the two species. Lucania parva had high survival at all salinities. Lucania goodei had high survival at 0 and 10 ppt, but low survival at 20 and 30 ppt. Hence, there is no evidence for a trade-off in the early life-history stages between these two species. Current research is investigating whether trade-offs occur at later life-history stages.
The Jefferson complex comprises the Jefferson Salamander (Ambystoma jeffersonianum) and the Blue-spotted Salamander (Ambystoma laterale), in addition to unisexual salamanders, which present various combinations of the nuclear genome of the two bisexual species and show different levels of ploidy. The unisexuals arose by an ancestral hybridization event, and they all share a similar mitochondrial haplotype clearly different from that of the bisexual species. Although adults of A. jeffersonianum and A. laterale are usually easily differentiated morphologically, unisexuals can be difficult to identify visually because they may possess intermediate characters, or morphological traits from either of their bisexual counterparts. In the present study, we introduce a novel way to discriminate between bisexual and unisexual salamanders of the Jefferson complex based on taxon-specific primers designed in the mitochondrial cytochrome b region. This molecular approach allows for a simple, rapid, and non-invasive identification of unisexuals, using a single polymerase chain reaction (PCR) and small tissue samples that can easily be obtained from live specimens. We believe that this approach will be useful to screen a large number of individuals quickly in order to identify populations of the Jefferson Salamander, a crucial step towards the conservation of this threatened species.
The Scarlet Shiner (Lythrurus fasciolaris) and Redfin Shiner (L. umbratilis) are common small minnow species usually exhibiting a parapatric geographic distribution within the Ohio River basin. Historical collection records suggest several areas of possible syntopy along the periphery of distributional ranges, with suspected hybridization based upon observed intermediate morphology of nuptial males. Nuptial males from nine localities with suspected hybridization were collected in June and July 2004; morphometric, meristic, tuberculation, and coloration data were collected and analyzed to test the hypothesis that these species are hybridizing. Based on univariate and multivariate analyses and qualitative assessment of the morphological data, the Green River, Kentucky River, and Salt River drainages in Kentucky and the Scioto River drainage in Ohio all have populations with evidence of past gene flow. Comparisons of current observations with historical collections show an eastward range expansion of L. umbratilis with replacement of L. fasciolaris. The introgression of morphological characters toward those of L. umbratilis in the Green River, Salt River, and Scioto River drainages imply that hybridization may play a direct role in this range expansion. The novel morphology of specimens from Eagle Creek, Kentucky River drainage suggests that hybridization also has resulted in the development of a static, morphologically distinct hybrid swarm. In each case, environmental conditions seem closely linked with the occurrence and net effects of hybridization between these two species.
Gaps in recent studies of hognosed pit vipers in the genus Porthidium have left researchers with an incomplete estimate of the evolutionary history of this group. Mitochondrial DNA sequence data from the poorly known P. hespere and additional Porthidium sequences obtained from GenBank were used to re-analyze the phylogenetic relationships of Porthidium. Using sequence data from the South American Porthidium, we also updated a previous molecular clock calibration based on the uplift of the Isthmus of Panamá, and utilized this updated calibration to evaluate the phylogeography of arid-adapted Porthidium. Results from Bayesian Markov chain Monte Carlo phylogenetic methods underscore the historical pattern of bi-directional dispersal into and out of South America within Porthidium, and place P. hespere as the sister species to P. dunni. The three species of arid-adapted Porthidium distributed across the Pacific coast of southern Mexico and northern Central America may have diverged in the late Miocene after the enlargement of the Río Balsas drainage following the formation of the Mexican Transvolcanic Belt and the volcanic uplifting across the Chiapan–Guatemalan highlands.
Debido a la ausencia de algunas especies en los estudios recientes de las nauyacas nariz de cerdo del género Porthidium, los investigadores no tienen una estimación completa de la historia evolutiva de este grupo. Se utilizaron nuevas secuencias de ADN mitocondrial de la poco conocida P. hespere y otras secuencias obtenidas de GenBank para reanalizar las relaciones filogenéticas de Porthidium. Usando secuencias de Porthidium sudamericanas, también se actualizó una calibración previa del reloj molecular basada en la elevación del Istmo de Panamá, y esta calibración actualizada se utilizó para evaluar la filogeografía de las especies de Porthidium adaptadas a la aridez. Los resultados de los métodos filogenéticos Bayesianos Markov chain Monte Carlo enfatizan el patrón histórico de dispersión bidireccional hacia y desde Sudamérica en Porthidium, y ubican a P. hespere como especie hermana de P. dunni. Las tres especies de Porthidium adaptadas a la aridez de la costa Pacífica del sur de México y norte de Centroamérica podrían haber divergido en el Mioceno tardío después del ensanchamiento del drenaje del Río Balsas que siguió a la formación del Eje Neovolcánico y la elevación volcánica de las tierras altas de Chiapas y Guatemala.
We describe a new species of Hypsiboas of the Hypsiboas pulchellus species group from highland streams of the Atlantic Forest of southeastern Brazil. Vocalizations, egg-mass, and tadpole are also described. We compared the new species with other species of the Hypsiboas pulchellus species group. The new species is most similar to Hypsiboas semiguttatus, its sister species, and Hypsiboas curupi, from which it differs in advertisement call and larval morphology. We provide information on natural history, phylogenetic relationships, embryos, geographic distribution, and conservation.
We used 991 bp of mtDNA (D-loop/ND4L/ND4) and eight microsatellite loci to examine population structure and genetic diversity of Catostomus plebeius from nine localities across the northern part of its range in New Mexico. Two phylogeographic regions (Mimbres and Rio Grande) were defined by phylogenetically distinct collections of mtDNA haplotypes. Mismatch distribution analysis and relatively deep coalescence of haplotypes within the upper Rio Grande suggested rapid population expansion of Rio Grande populations following putative colonization from the ancestral Cabeza de Vaca lake system during the Miocene. Mitochondrial haplotypes indicated that individuals from Palomas Creek (near present-day Elephant Butte Reservoir) shared most recent common ancestry with the Rio Grande phylogeographic region. Microsatellite diversity and allele identity supported the hypothesis of native status of C. plebeius from Sapillo Creek in the Gila River drainage. Analysis of molecular variance within and among samples from the upper Rio Grande suggested low levels of historic gene flow across that basin, with ΦST = 0.19 and FST = 0.14 for mtDNA and microsatellites, respectively.
Utilizamos marcadores mitocondriales (991 bp) y ocho microsatélites (DNA) para examinar la diversidad y la estructura genética de poblaciones de Catostomus plebeius en nueve localidades en Nuevo México. Se identificaron dos regiones filogeográficas distintas: el Mimbres (Río Mimbres y Sapillo Creek) y el Río Grande (Palomas Creek y localidades a lo largo del Río Grande). El análisis demográfico mitocondrial permitió discernir una estabilidad histórica en la población del Río Mimbres, así como una expansión de poblaciones en el Río Grande después de la colonización del lago Cabeza de Vaca a partir del Plioceno Tardío. Datos genéticos sugieron que la población en Palomas Creek (cercano Elephant Butte Reservoir) es relacionado a las poblaciones in el Río Grande. Un alto número alelos únicos en los microsatélites encontrados en Sapillo Creek (un tributario del Río Gila), sugiere que la población es nativa y que pudo haber colonizado el área durante un proceso de captura de un tributario del Río Mimbres. Encontramos una estructura genética de moderada a fuerte en el mitocondrial y microsatélite DNA entre los tributarios superiores del Río Grande, con ΦST = 0.19 y FST = 0.14, respectivamente.
Diamondback Terrapins (Malaclemys terrapin) are distributed in brackish water habitats along the U.S. east coast from Massachusetts to Texas, but many populations may be in decline. Whereas ample morphological, behavioral, and reproductive information has been collected for terrapins living in temperate salt marsh habitats, comparatively little is known about mangrove terrapins. To understand population structure of mangrove M. terrapin living in a wilderness area, we conducted a capture–recapture study in the remote, protected Big Sable Creek complex of Everglades National Park, Florida. The goals of the study were to collect baseline demographic data and to compare population structure and growth rates of mangrove terrapins with what is known for more well studied salt marsh terrapins in locations that experience human-imposed threats. We marked 300 terrapins; the sex ratio was 1 female:1.2 males. Considerable sexual size dimorphism was apparent, with reproductively mature females three times larger (by mass) than mature males. Eighty percent of females and 94% of males were classified as mature, based on straight plastron length (SPL). For a subset of terrapins not yet at maximum size (n = 39), we measured growth as a change in straight carapace length over time of 0.3–26.4 mm/yr for females (n = 26) and 0.9–14.5 mm/yr for males (n = 13). Our study presents the first demographic data on mangrove M. terrapin in the coastal Everglades.
Rhinodoras is newly diagnosed within Doradidae by its unique combination of coloration (sides darkly mottled, usually with wide dark bars, light midlateral stripe absent) and lip morphology (labial tissue thick, fleshy, considerably expanded at corners of mouth forming rounded flap-like extensions with entire margins, all surfaces rugose with low, rounded, and tightly spaced papillae, and distal margin of lower lip draped over bases of outer and inner jaw barbels, at times nearly encircling the latter). Three previously described species are considered valid, R. thomersoni (Lake Maracaibo basin), R. boehlkei (Amazonas), and R. dorbignyi (Paraguay–Paraná), and two new species are described. Rhinodoras armbrusteri from the Branco/Essequibo basins is diagnosed by having ventral surfaces with dark pigment, anterior midlateral plates moderately deep with dorsal and ventral wings subequal in depth, sum of midlateral plates 57–60, midlateral plates anterior to vertical through pelvic-fin origin usually five, tympanal portion of lateral-line canal moderately ossified with three distinct plates, postcleithral process moderately short and broad, adipose eyelid moderate to large, pectoral-fin rays usually eight, and one-part gas bladder. Rhinodoras gallagheri from the Orinoco basin is diagnosed by having ventral surfaces pale, anterior midlateral plates shallow to moderately deep with dorsal and ventral wings about equal in depth, midlateral plates anterior to vertical through pelvic-fin origin usually five, tympanal portion of lateral-line canal weakly ossified with two to three emergent plates, postcleithral process moderately long and narrow, adipose eyelid moderate to large, pectoral-fin rays usually eight, and one-part gas bladder. Rhinodoras is the only doradid genus with extant species in both trans- and cis-Andean drainages.
Se actualiza el diagnosis del género Rhinodoras dentro de la familia Doradidae en base a su patrón de coloración; éste que consiste en lo siguiente: costados oscuramente moteados, carencia de una franja media lateral clara, y generalmente posee tres franjas verticales oscuras; estos caracteres en combinación con una morfología labial especial que en tener el tejido labial grueso, carnoso, y expandido considerablemente en las esquinas de la boca para formar una solapa redondeada sin borde aserrados; la superficie de este tejido es rugosa, con papilas bajas, redondas y casi tocándose entre si; el margen distal del labio inferior pasa por encima de las bases de las barbillas mentonianas externas e internas, a veces casi encierran a éstas últimas. Se consideran válidas tres especies previamente descritas: R. thomersoni (cuenca del Lago de Maracaibo), R. boehlkei (Amazonas), and R. dorbignyi (Paraguay–Paraná), y se describen dos especies como nuevas. Rhinodoras armbrusteri del cuencas del Branco/Essequibo se distingue en poseer las superficies ventrales con pigmento oscuro, las placas laterales medias anteriores son moderadamente profundas y con las alas dorsales y ventrales desiguales en altura; la suma de los conteos de las placas medias laterales de ambos lados oscila entre 57 y 60; presenta cinco placas medias laterales anteriores hasta llegar al nivel del origen de las aletas pélvicas; la porción encima del tímpano del canal de la línea lateral está bien osificada y consiste de tres placas distintas; el proceso postcleitral es moderadamente corto y ancho; el ojo es de moderado a grande, los radios pectorales generalmente son ocho, y la vejiga natator
Leeches are one of the most commonly observed parasites of freshwater turtles. We used baited hoop traps to capture 433 turtles belonging to five species (Apalone spinifera, Chelydra serpentina, Chrysemys picta, Sternotherus odoratus, and Trachemys scripta) to determine the host (species, microclimate use, sex, reproductive stage, and body size) and environmental characteristics (month of capture, turtle abundance, vegetation, turbidity, pond size, and availability of basking structures) that affected leech parasitism in Illinois ponds. Leech prevalence on turtles varied significantly among turtle species, was highest on bottom-walkers and adults, and varied throughout the year. Leech intensity was highest on larger turtles and in turbid ponds. The results from this study display the importance of utilizing turtle assemblages for examining overall trends in host–parasite dynamics, demonstrate the influence of environmental characteristics on leech parasitism, and provide baseline data for future studies examining leech parasitism on turtles.
Total immunoreactive corticosteroid (IRC) levels (adjusted for fish mass; ng/g) were measured in whole-body homogenates of 2- and 8-months old Whitetail Shiners (Cyprinella galactura) and 4-months old federally threatened Spotfin Chubs (Erimonax monachus) exposed for 48 hours to varying suspended sediment concentrations (SSC; 0, 25, 50, 100, and 500 mg/L). Hydrophobic fractions were extracted from individual frozen fish after sonication and centrifugation of tissues. Extracts were resuspended in a buffer compatible with a commercially available enzyme-linked immunosorbent assay (ELISA) kit. Serially diluted concentrations of cortisol and extracts collected from unstressed fish were used to standardize the assay. Two-months old C. galactura had the highest resting level of whole-body IRC at 0 mg/L SSC. They also elicited the greatest response (three- to four-fold increase) when exposed to SSCs greater than 25 mg/L. Resting whole-body IRC levels were lowest in 8-months old C. galactura. For these fish IRC levels at 25, 50, and 100 mg/L SSC were similar to controls. Four-months old E. monachus showed a non-linear response with a possible threshold effect between 50 and 100 mg/L. At SSC greater than 100 mg/L E. monachus demonstrated a three-fold increase in whole-body IRC levels over control fish. Exposure to SSC levels greater than 100 mg/L caused a significant increase in IRC levels above baseline in both species and in all three life stages. This investigation shows that whole-body levels of IRC in young minnows increase dramatically upon exposure to SSCs greater than 25 mg/L. These data suggest that even moderate levels of suspended sediment (i.e., 100 mg/L) can severely stress young-of-year E. monachus. The imperilment of E. monachus may in part be due to stress imposed on young fish by elevated suspended sediment.