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Based on histological cross-sections of the frog Phrynohyas resinifictrix, we present evidence suggesting the presence of a pumping mechanism associated with the function of the vomeronasal organ. We also propose that the fluid supply for the mechanism originates from gland secretions, which may also play a role in providing the vomeronasal organ with chemical cues.
We studied the reproductive and trophic ecology of a group of aquatic and semi-aquatic snakes that face severe hunting pressure in Cambodia. Over a two-year period we sampled hunters' catches, measuring and dissecting a total of 8982 specimens of seven snake species, five of which belong to the family Homalopsidae. The seven species—Enhydris enhydris, Enhydris longicauda, Homalopsis buccata, Enhydris bocourti, Erpeton tentaculatus, Xenochrophis piscator, and Cylindrophis ruffus—all inhabit Tonle Sap Lake, the largest lake in South-East Asia. All species are sexually dimorphic in either body size or tail length. The larger species, E. bocourti and H. buccata, have a larger size at maturity, and the non-homalopsids, X. piscator and C. ruffus, have the highest and lowest fecundities, respectively. Clutch size increases significantly with female body size in all species, and with body condition in E. enhydris. Our data also suggest that relative investment in reproduction increases with size in E. enhydris, which has the largest sample size. All species except one are synchronized in their timing of reproduction with the seasonally receding flood waters of the lake. There was variation in both the frequency of feeding and the prey size and type among species, with the homalopsids more similar to one another than to the other non-homalopsid species. The prey to predator mass ratio ranged from 0.04 to 0.1 in the homalopsids, compared to 0.15 to 0.17 in the non-homalopsids. There was also variation in the feeding frequency between the sexes that differed between species and six species continued to feed while gravid. These detailed life history analyses can help provide a basis for assessing conservation options for these heavily exploited species.
We studied daily growth-increment formation in the otoliths of early life history stages of Sharpnose Shiner, Notropis oxyrhynchus, and Smalleye Shiner, Notropis buccula, in the Brazos River, Texas to investigate the influence of streamflow and intermittency on the production of young. Both species successfully produced offspring throughout a four- to five-month period. Successful reproduction occurred over a longer period in 2004 than in 2003. The results of our study revealed that recruitment by N. oxyrhynchus and N. buccula populations in the Brazos River, Texas are related to streamflow in two principal ways. First, the greatest proportion of young-of-year produced during the reproductive season is associated with elevated streamflow events. Second, no young-of-year are successfully produced during periods of intermittency when the river is not flowing. Our results suggest that the focus of conservation efforts, which to date have primarily concentrated on creating proper streamflow conditions for spawning, should also be focused toward ensuring proper conditions for survival of ova and young larvae.
Reproductive activities can impose fitness costs as well as benefits. In most anuran species, males clasp females for prolonged periods prior to gamete release, and intuition suggests that the male's presence may impair the female's ability to move about and to feed. We tested the prediction that female locomotion and feeding would be reduced during amplexus in laboratory experiments with Cane Toads, Bufo marinus. Amplexus reduced the female's locomotor (sprint and swim) performance, with the degree of locomotor impairment (speed and distance per hop) dependent upon the body size of the amplectant male for trials of terrestrial locomotion, but not for aquatic locomotion. Amplexus also reduced feeding rates in females; amplectant males did not feed at all. Overall, our data confirm that amplexus imposes locomotor and feeding costs to female Cane Toads, and suggest that this distinctive posture may generate sexual conflict in at least some anuran species.
A new species of frogfish of the teleost order Lophiiformes, family Antennariidae, is described from three specimens collected in shallow waters off Ambon and Bali, Indonesia. A member of the antennariid genus Histiophryne, the new taxon differs substantially from its congeners in having a broad flat face, surrounded by thick, fleshy, laterally expanded cheeks and chin, with eyes directed forward; skin of the body thick and loose, forming conspicuous fleshy folds that envelop the unpaired fins; a remarkable pigment pattern of white swirling stripes radiating from the eyes and continuing back to the body and tail; genetic divergence in the nuclear recombination activation gene-2 (RAG2), cytochrome oxidase-I (COI), and 16S rRNA genes; and a set of behavioral traits not previously known in fishes. The new species is described and compared with its congeners. Notes on habitat, locomotion, pigment pattern and camouflage, predation and defense, and reproduction and parental care are also provided.
We determined the use of refugia by salamanders during daytime in summer and characteristics of these refugia in Salamandrella keyserlingii at Shaamar, Mongolia. Refugia were located at mean distance of 4.17 m from the edge of the water. Among these refugia, blind tunnels within grasslands (mean distance = 7.50 m) were farther apart than open burrows distributed along a steep slope of a pond-shore (2.49 m). Subterranean burrows having mean depth of 15.4 cm were utilized temporarily (individuals captured only once) with proportional habitat use of 0.704 (19/27 refugia). Mean temperature was lower in burrows/under logs (16.22°C) than in ambient air (26.70°C) or among grasslands (25.10°C). Mean relative humidity was higher in burrows/under logs (85.54%) or among grasslands (75.53%) than in ambient air (48.33%). Mean illumination intensity was 27.0 lx in burrows/under logs and 17,188.1 lx on the surface out of refugia. Mean soil pH was 7.52 beneath salamanders in refugia.
Baryancistrus beggini, new species, is described from the upper Río Orinoco and lower portions of its tributaries, the Río Guaviare in Colombia and Río Ventuari in Venezuela. Baryancistrus beggini is unique within Hypostominae in having a uniformly dark black to brown base color with a blue sheen in life, and the first three to five plates of the midventral series strongly bent, forming a distinctive keel above the pectoral fins along each side of the body. It is further distinguished by having a naked abdomen, two to three symmetrical and ordered predorsal plate rows including the nuchal plate, and the last dorsal-fin ray adnate with adipose fin via a posterior membrane that extends beyond the preadipose plate up to half the length of the adipose-fin spine.
Se describe una nueva especie, Baryancistrus beggini, del alto Río Orinoco y las partes bajas de sus afluentes: el río Guaviare en Colombia, y el río Ventuari en Venezuela. Baryancistrus beggini es la única especie entre los Hypostominae que presenta fondo negro oscuro a marrón sin marcas, con brillo azuloso en ejemplares vivos. Las primeras tres a cinco placas de la serie medioventral están fuertemente dobladas, formando una quilla notable por encima de las aletas pectorales en cada lado del cuerpo. Baryancistrus beggini se distingue también por tener el abdomen desnudo, dos o tres hileras de placas predorsales simétricas y ordenadas (incluyendo la placa nucal) y el último radio de la aleta dorsal adherido a la adiposa a través de una membrana que se extiende posteriormente, sobrepasando la placa preadiposa y llegando hasta la mitad de la espina adiposa.
The taxonomic status of Hylambates rufus aubryioidesAndersson, 1907, a taxon rarely treated in the literature and considered to represent a junior synonym of Leptopelis modestus, is re-evaluated. The taxon is redescribed and a lectotype is designated. Morphological comparisons revealed that it is neither conspecific with L. modestus, nor with L. calcaratus, as suggested by an unpublished identification tag. Instead, no morphological characters distinguish the taxa L. aubryioides and L. omissus. Leptopelis aubryioides (Andersson, 1907) is considered a valid species and Leptopelis omissus Amiet, 1992 is placed as its junior synonym.
A new species of the Anolis crassulus group is described from the cloud forests of Parque Nacional Montaña de Yoro, Departamento de Francisco Morazán, Honduras. This species is distinguished from other members of the A. crassulus group by hemipenial morphology and characteristics of pholidosis. Apparently restricted to a single cloud forest site in central Honduras, the new species qualifies as Critically Endangered under IUCN red list criteria.
Se describe una nueva especie del grupo Anolis crassulus de los bosques nublados del Parque Nacional Montaña de Yoro, Departamento de Francisco Morazán, Honduras. Esta especie se distingue de otros miembros del grupo A. crassulus por la morfología de los hemipenes y características de escutelación. Aparentemente se encuentra restringido a un unico sitio del bosque nublado en Honduras central, la nueva especie se encuentra en la categoría En Peligro Crítico, bajo los criterios de la Lista Roja de la UICN.
Social control of sex determination has been reported in juvenile Midas Cichlids, Amphilophus citrinellus, held in large captive groups. In adults, males are typically larger than females. Large body size relative to group-mates was proposed to cause male differentiation, and small body size thought to cause female differentiation. More recent evidence has found no association between body size and sex in juveniles, a pattern inconsistent with the hypothesis that sex determination is controlled socially in this species. The current experiments were performed in order to determine if larger body size in adult males than in adult females is due to faster post-maturational growth, rather than due to larger juveniles differentiating as males and smaller juveniles differentiating as females. Juvenile Amphilophus cichlids from four lineages were divided into experimental groups, individually marked, and raised to maturity. Relative body size did not control sex determination. The observed growth patterns indicate that differences in body size between the sexes in adults is due to faster post-maturational growth in males than in females.
In urbanized landscapes, golf course ponds may provide the only remaining habitat for semi-aquatic animals. Eastern Mud Turtles (Kinosternon subrubrum), which rely heavily on both aquatic and terrestrial habitats, may face challenges on golf courses, which typically have significantly modified and fragmented landscapes. We conducted a radio-telemetric study of 11 mud turtles inhabiting a golf course pond in the western Piedmont of North Carolina to investigate their terrestrial activity and habitat selection in a fragmented landscape. Most turtles moved to terrestrial habitats in late summer and emigrated a mean distance (± SE) of 187.2 ± 67.4 m and moved a mean straight line distance (± SE) of 119.3 ± 47.4 m from the pond. We determined habitat selection using logistic regression to compare turtle locations with random locations and found that mud turtles selected forested habitats with moderate canopy cover and no grass. Mud turtles also selected habitat containing herbaceous vegetation and woody debris as overwintering locations. Mud turtles did not select heavily disturbed habitats with limited canopy cover and pavement or cut grass associated with fairways, roughs, and residential lawns. Overall, our study suggests that maintaining relatively undisturbed forested habitat within fragmented urban landscapes, such as those found on golf courses, may allow for the persistence of these semi-aquatic turtles. Information from this study can be used to better understand critical upland habitat requirements of other semi-aquatic species inhabiting fragmented landscapes and aid in the implementation of habitat management plans.
Sources of body temperature (Tb) variation in freshwater turtles are known for very few species. Using surgically implanted, temperature-sensitive radiotransmitters in Midland Painted Turtles (Chrysemys picta marginata), we assessed Tb variation in relation to sex, microhabitat use, weather conditions, and water temperature (Tw) in a marsh system in northern Michigan. Diel Tb cycling occurred regardless of weather conditions and included monotonic declines during late evening and early morning hours, a late morning warming phase, a mid-day spike, and afternoon oscillations. Males maintained significantly higher mean Tb than females during the 0000–0600 h time period but not at other times during the day. During the nesting season and during all summer and fall months, sex did not explain any variation in mean daily Tb, but males had significantly lower mean daily Tb variability (CV Tb) than females. Mean daily Tb and CV Tb were significantly lower on overcast days than on sunny days, and females maintained significantly greater mean daily Tb than males on cloudy days. Habitat use affected mean daily Tb, where turtles that used the open-water microhabitat had higher and less variable Tb than turtles that used the edge microhabitat for at least part of the day. Overall, mean total daily distance moved (TDDM) was greater in males than in females although the effect was weak. Mean TDDM was significantly greater on sunny days than on cloudy days, and greater in turtles that used open-water microhabitats than in turtles that used only the edge microhabitat. Mean daily Tb began to decline in October, but mean TDDM, and therefore activity, did not occur until November. Daily movements ceased when Tw fell to 2.0–3.9°C in December and January.
Phylogenies based on DNA sequence data are providing a range of new insights into relationships within Acanthomorpha, particularly in cases where morphological characters have been scanty or misleading. Molecular phylogenetic analyses of the perciform suborder Gobioidei have illuminated relationships within and among groups, with recovered clades generally corresponding to groups identified based on morphological characters. This study integrates and expands previous molecular phylogenetic hypotheses to infer a comprehensive gobioid phylogeny, including a variety of outgroup taxa included to confirm sister taxon identity and position of the group among other acanthomorphs. This and other phylogenetic hypotheses indicate that Gobioidei is part of a clade that also includes Apogonidae, Pempheridae, and Kurtidae. These groups share characteristics of the skeleton, soft tissues, and reproductive ecology. A new six-family clade-based classification of Gobioidei is presented, and Gobioidei, Apogonoidei (Apogonidae Pempheridae), and Kurtoidei are placed as suborders of a resurrected Gobiiformes. Patterns of morphological character evolution among gobioids are then examined in the context of the molecular phylogeny, and their distribution is correlated with species diversification and phylogenetic imbalance. The two largest gobioid clades, Gobiidae and Gobionellidae, differ significantly in species richness, perhaps due to increased diversification in marine habitats by gobiids. The phylogeny of Gobiidae exhibits a convex plot of lineages through time, consistent with an elevation of speciation rate early in the clade's history. The γ statistic is consistent with this increase, but is not significant after correction with the Monte Carlo Constant Rates (MCCR) test.
The Eyelash Palm-pitviper, Bothriechis schlegelii, is reported to be a nocturnal ambush predator that preys upon a wide variety of vertebrates. This study demonstrates that B. schlegelii has a greater temporal activity range than previously documented. Bothriechis schlegelii moves most frequently at night, is capable of capturing mobile prey from daytime perches, and consumes diurnally- and nocturnally-active prey. An ability to consume prey during both night and day increases the importance of the role of B. schlegelii as a predator of small vertebrates.
A new species of Alestes from the Mpozo River in the Bas Congo Province of the Democratic Republic of Congo is described and diagnostic characters for the genus are presented. Alestes inferus, new species, is differentiated from all other members of the genus by its lower and non-overlapping lateral-line scale count (31–33 versus 36–51) and its reduced and non-overlapping vertebral count (39–40 versus 41–49). Within Alestes, the new species appears to be most closely related to A. macrophthalmus and A. liebrechtsii, based on the shared possession by these three species of a tubular, bony extension enclosing the olfactory nerve on the lateral ethmoid, and bifurcated lateral-line canals terminating in two pores. Alestes liebrechtsii and A. inferus are the only species of the genus known from the lower Congo River.
Like many species of amphibians, Boreal Toads (Bufo boreas boreas, Bufonidae) are declining throughout portions of their range. Recent efforts have focused on describing the ecology of this species, yet few studies have evaluated demographic characteristics that may influence the persistence of Boreal Toad populations. Because Boreal Toads often convey themselves down valleys via stream channels in some areas, we set upstream-facing hoop nets in early to late summer in several first- to third-order tributaries in two western Montana river basins to assess the sizes of individuals using streams and examine temporal and spatial variation in captures. We made 923 captures of juvenile and adult Boreal Toads. Adult females were up to 125 mm snout–vent length, whereas males never exceeded 105 mm. Females tended to be heavier than males and female weights were significantly more variable. Early-summer captures were dominated by juvenile toads <40 mm, late summer catches were largely of individuals >70 mm, and toads of intermediate size were rare throughout. In tributaries of one river basin, captures of toads were more widely distributed in late summer than in early summer, whereas in tributaries of the other basin catches were similarly distributed in both periods. We infer from these patterns that frequent and perhaps far-ranging movements by juveniles and adults are typical of Boreal Toads in this region. We contend that netting streams in summer represents a useful complement to breeding site surveys for understanding the demographics and distribution of Boreal Toads, and perhaps other non-breeding amphibians near streams.
Lycodes diapterus, the type species of Furcimanus, has been divided into as many as three subspecies (L. diapterus diapterus, L. d. beringi, and L. d. nakamurae). Although L. d. nakamurae has been broadly recognized as a distinct species by recent authors, the status of L. d. beringi is unresolved, and several authors have noted the need for a comprehensive morphological study of L. diapterus. Based on an examination of nearly 500 specimens collected from Kamchatka to California, we herein recognize Lycodes beringi as a valid species distinguished from L. diapterus by meristics and squamation. Lycodes beringi is distributed from southeastern Kamchatka through the Bering Sea, Commander and Aleutian Islands, Gulf of Alaska, and south along the North American west coast to Puget Sound, while L. diapterus ranges from the Pacific coast of Vancouver Island south along the U.S. west coast to southern California. In this report we document the morphological variation present in L. diapterus and L. beringi and designate a lectotype for L. beringi. We also provide diagnoses, descriptions, and distribution information for both forms, and compare them with closely related congeners, providing comments on the subgenus Furcimanus.
Rana okaloosae is endemic to northwestern Florida and is sympatric with R. clamitans clamitans, its closest relative and possibly its main interspecific competitor. We evaluated the movements, dynamic interactions, and nearest neighbor distances of male R. okaloosae and R. c. clamitans in Okaloosa County, Florida. Mean minimum daily distances moved and maximum daily distances moved were greater for R. c. clamitans than R. okaloosae. Dynamic interactions tended to be positive and suggested that there were positive associations between individuals of the two species. Further, nearest neighbor analyses suggested that calling males of both species were positioned in a clumped distribution on any single night. The intraspecific and interspecific interactions of these species were complex and suggested that these species may have selected similar calling locations and appeared not to exclude either conspecifics or heterospecifics.
A new species, Steindachnerina notograptos, is described from the middle portions of the Rio Tocantins drainage, Brazil. The possession of a small, fleshy, lobulate body situated on each side of the posterior limit of the medial fold of the buccopharyngeal complex is autapomorphic for S. notograptos. The combination of other aspects of the buccopharyngeal complex along with meristic and pigmentation features further distinguish the species from all of its congeners.
We describe a new species of Noblella from the upper Cosñipata Valley in southern Peru (Cusco Region). Specimens were found in the leaf litter of a cloud forest between 3025 and 3190 m elevation. The most distinctive character of the new species is its diminutive size (maximum SVL female 12.4 mm, male 11.1 mm). With an average snout–vent length of 11.4 mm (n = 7) in adult specimens, the new species is the smallest Andean frog, and one of the smallest anurans in the world. The new frog is rare (between 30 and 75 frogs/ ha) and found only in montane scrub and forest habitats near the ecotone with the high-Andean puna grasslands. Although the amphibian fungal infection (Batrachochytrium dendrobatidis) has been recorded in southern Peru, no infections were detected in the new species.
Etheostoma akatulo, the Bluemask Darter, is described from upper Caney Fork River System of the middle Cumberland River drainage, Tennessee. It is presently known from four tributaries of Great Falls Reservoir on the eastern Highland Rim and is listed as federally endangered. The new species differs from other species of the subgenus Doration by having fully scaled cheeks, complete lateral line, breeding males with bright blue pigment completely covering the lower face, and breeding males with soft dorsal and anal fins lacking orange and blue pigment. Specimens are compared with nominate E. stigmaeum from four drainages and E. jessiae. Etheostoma akatulo typically occurs over sand and gravel substrates downstream of riffles, in moderate runs, or along margins of pools. It inhabits a 37-km reach of Collins River but is found in reaches of 4.3 km or less in Rocky River, Cane Creek, and Caney Fork River. Threats to the species include gravel dredging, pesticides, siltation, and acid mine drainage.
Halichoeres socialis was recently described as a new species of labrid fish from Caribbean reefs off Belize, Central America. The initial description was based upon a collection of initial phase juveniles, females, and males. Subsequently, the colorful terminal male phase was photographed, collected, and is now described. This species is, so far, known only from the mangrove cays, inside the barrier reef system of Belize.
Several studies of the ecology of mesopelagic fishes off Hawaii published in the 1970s and 1980s reported the existence of as many as two undescribed species in the Pacific Ocean. Diagnosed primarily on the basis of postorbital and accessory orbital photophore size and size at maturity, three new species are described: P. liemi, new species, and P. tantillux, new species, both endemic to tropical and subtropical Indo-Pacific water masses, and P. lucingens, new species, a species distributed in the subtropical and tropical Pacific and South Atlantic oceans. Photostomias liemi and P. tantillux represent smaller forms, with females maturing at standard lengths less than 70 mm, making these species the smallest sexually mature stomiids. Despite the analysis of some 35 morphometric and meristic characters, females of P. liemi are indistinguishable from females of P. atrox. The current study brings the total number of valid species of Photostomias to six. A key to these six species is provided.
In aquatic systems, a long-standing question is why chemical cues from some diets consumed by a predator induce strong anti-predator responses in prey while other diets induce weak or no responses. We performed an experiment to determine if strong prey responses to particular predator diets are due to prey being closely related to the predator's diet (i.e., phylogenetic relatedness) or due to prey coexisting with the predator's diet and thereby sharing a risk of predation. We compared the behavior of Gray Treefrog tadpoles (Hyla versicolor) to cues from a dragonfly nymph (Anax junius) that consumed either conspecific Gray Treefrogs, one of six diets that commonly coexist with Gray Treefrogs (spanning a wide range of phylogenetic relatedness), or one diet that is closely related to Gray Treefrogs but has an allopatric range that has not overlapped for at least 20,000 yrs. We found that tadpoles could discriminate among the diets and that the magnitude of behavioral response supported the hypothesis of diet phylogenetic relatedness and refuted the hypothesis of diet coexistence.
Trichomycterus hualco, new species, is described from an Andean stream in the Provincia de La Rioja, Argentina. The new species is distinguished from other species of Trichomycterus in the combination of the number of odontodes on the opercle and interopercle, the degree of exposure of the odontodes on the interopercle, the form of the premaxillary teeth, the presence of papillae-like structures on the body, the number of vertebrae, the position of the first proximal dorsal-fin pterygiophore, the form of the supraorbital canal within the frontal, the length of the lateral-line canal, and various meristic features.