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We exposed two size classes of Banded Sculpins, Cottus carolinae, to alarm cue secretions from an adult Hellbender (Cryptobranchus alleganiensis) or to a blank control and examined foraging responses. Banded Sculpins exhibited size-dependent responses, with small individuals exhibiting avoidance behavior and large individuals exhibiting increased foraging behavior. These data suggest that Banded Sculpins undergo an ontogenetic shift in response to Hellbender alarm cues that corresponds to changes in predation risk and foraging profitability.
We observed agonistic behavior among larval Ambystoma opacum, A. jeffersonianum, and A. maculatum in intra- and interspecific pairwise comparisons to determine if sympatric species exhibit unique behavioral responses to the presence of con- or heterospecific larvae, if they respond similarly to variation in competitor size, and if species identity is a reliable predictor of predation and cannibalism versus strictly nonlethal competitive interactions as an outcome of larval aggression. Each species exhibited a unique suite of behavioral responses associated with species and competitor size. Ambystoma opacum displayed high levels of aggression, most often towards conspecifics, but these behaviors rarely resulted in predation. Conversely, A. jeffersonianum displayed aggression frequently and often consumed both con- and heterospecific larvae. Furthermore, this species did not reduce aggression even in the presence of larger larvae. Ambystoma maculatum displayed relatively low levels of aggression under most circumstances. We conclude that these characteristic responses are associated with species-specific morphological and developmental features and the temporally staggered pattern in which these species appear in ponds. These observations highlight the importance of these traits to behavioral divergence among ecologically similar taxa occurring in sympatry.
We determined whether Eleutherodactylus coqui exhibits clinal variation in male advertisement call parameters across its native Puerto Rico and introduced range of Hawaii. In the laboratory, we determined whether clinal variation in call parameters were a result of body size or temperature. Calls correlate with elevation in both Puerto Rico and Hawaii in the following ways: negative for fundamental frequency of each call syllable (Co and Qui), positive with the duration of each call, negative with call rate (calls per minute), and no relationship with call intensity. In the laboratory, we found the negative relationship between elevation and call frequency was best explained by larger body sizes at higher elevations, and that the positive and negative relationships between elevation and call duration, and elevation and call rate, respectively, were best explained by lower temperatures at higher elevations. While frogs in Hawaii exhibited the same relationships between elevation and call parameters found in Puerto Rico, they exhibited less variation in call frequency with elevation because they had less variation in body size. Differences in call duration and rate between Hawaii and Puerto Rico reflected lower temperatures in Hawaii at similar elevations. While individual frogs are not louder in Hawaii, choruses may appear louder where densities are higher.
The Massasauga Rattlesnake (Sistrurus catenatus) occurs from extreme southeastern Canada to northern Mexico, and most populations are highly threatened due to habitat loss and fragmentation. Although their range is reduced from historical levels, they may be locally abundant in appropriate habitat. We studied movement patterns, home range and core activity centers, habitat use, and prey abundance in a robust population of Desert Massasauga Rattlesnakes (S. c. edwardsii) in southeastern Colorado by radiotracking 36 snakes over four active seasons (May–October). In the spring, snakes made long-distance directed movements (mean = 1.89 km) from the hibernacula (shortgrass, compacted clay soils) to summer foraging areas (mixed-grass/Sand Sagebrush, sandhills). Summer activity was characterized by short distance non-directional movements, and snakes were most often observed at the base of Sand Sagebrush (Artemisia filifolia). Home ranges and core activity centers were significantly larger for males than for females, but daily movements, total distance moved, and range length did not differ significantly between sexes. Prey base surveys indicated a significantly higher abundance of both rodents and lizards in summer foraging grounds than at hibernation sites. Snakes returned to the hibernaculum area in October and appeared to hibernate individually in rodent burrows. Migration patterns exhibited by S. c. edwardsii are likely resource driven, with the migratory movements observed in the spring resulting in utilization of summer foraging habitat with more abundant prey. Conversely, hibernacula with greater thermal and structural stability in the shortgrass habitat (perhaps due to the compacted clay soils versus loose sandy soils) favor migratory return for torpor in the fall. At present, the main populations in Colorado occur far from developing regions in the state, but due to habitat loss and fragmentation resulting from projected agricultural expansion and urbanization, these populations may be threatened in the future.
Communication signals often function in multiple contexts such as territory defense, mate attraction, and predator deterrence. If signals indicate the quality of the signaler, then high rates of signal use may be associated with successful outcomes across multiple contexts. Here, I examined the relationship between signal use and interaction outcome during territorial defense and courtship bouts in field populations of the Brown Anole lizard, Anolis sagrei, in the middle of their breeding season. High bobbing rates, which are associated with high endurance in males of other lizard species, predicted both successful territorial defense and courtship bouts that resulted in copulation, while high rates of nodding, a signal typically associated with subordinate behavior during agonistic encounters, predicted unsuccessful outcomes in both contexts. Males performed dewlap extensions to females at a higher rate than to other males, independently of interaction outcome. In interactions with females, dewlap extension rates by males were higher during courtship bouts that did not result in copulations than during interactions preceding copulations. Assuming that increasing the rate of dewlap extensions benefits the signaler, this finding suggests that the use of the dewlap may play a larger role in stimulating or accelerating receptivity in an unreceptive female than in attracting an already-receptive female.
Paulasquama callis is a new genus and species of partially deplated ancistrin loricariid from the Waruma River, a tributary of the upper Mazaruni River, in northwestern Guyana. Paulasquama differs from all other described hypostomines by lacking plates in an oval area lateral to the mesethmoid, by having small plates in the dorsal series below the dorsal fin (less than half the typical size of other loricariids), and by having a fleshy keel on the preadipose plate and slightly anterior. The opercle of Paulasquama is sickle-shaped as in basal ancistrins, but has a posterior connection to the hyomandibula as in derived members of the Ancistrus clade.
The geographic variation and hemipenial morphology of Siagonodon brasiliensis are described based on a comprehensive sample, allowing the reappraisal of its generic identity, and the proposal of a new nomenclatural combination. We suggest that the presence of two supralabials, as mentioned in the original description of S. brasiliensis, is not a common feature for this species, occurring at low frequencies throughout its geographic distribution. Based on a diagnosis presented in a recently published paper, as well as on additional external traits and on hemipenial characters, we recognize Siagonodon brasiliensis as a species of the genus Tricheilostoma. In addition, a new species of worm snake of the genus Siagonodon is described from the savannas of the state of Tocantins, Brazil. The new species differs from other congeners by having a slightly acuminate snout in lateral and ventral views, subcircular rostral in dorsal view, and 12 scale rows around middle of tail. The diagnosis of the genus Siagonodon is revised and expanded based on direct observation of morphological characters.
†Sharfia mirabilis, a new genus and species of lophiid anglerfish from the Ypresian of Monte Bolca, northern Italy, is described from a single specimen residing among collections of the Muséum national d'Histoire naturelle, Paris. Together with †Lophius brachysomusAgassiz, 1835, known from three or four individuals also from Monte Bolca, †Sharfia mirabilis is the oldest member of the teleost family Lophiidae known to date based on articulated skeletal remains. It possesses several autapomorphic features as well as a unique combination of character states, especially in the structure of the opercular bones, which clearly separate it from all other known lophiiform fishes. Among extant lophiid genera, the new taxon shows perhaps the strongest phenetic resemblance to Sladenia and Lophiodes. †Sharfia mirabilis most likely inhabited inner shelf regions of the central Tethys Sea about 50 Ma, living at moderate depths on soft mud or sand bottoms, much like extant members of the family.
Two fossils from the diverse St Bathans Fauna from Early Miocene sediments in New Zealand are described and identified as from a large, probably terrestrial turtle. They are the first freshwater or terrestrial turtles to have been reported from the Cenozoic of New Zealand. Recent authors have used the absence of turtles and species they considered unlikely to raft to New Zealand to debunk the long held theory that an element of the New Zealand fauna was ancient and vicariant and had evolved on what David Bellamy called Moa's Ark. The discovery that large non-marine turtles were once present in New Zealand adds to a growing and diverse list of terrestrial taxa known from Zealandia shortly after its maximum inundation in the Late Oligocene. Many of these taxa, including a diverse herpetofaunal component, represent lineages endemic to New Zealand and had poor dispersal capabilities, supporting the long held view that a part of the Zealandian fauna was vicariant in origin.
Gymnotus tiquie, new species, is described from the Rio Tiquié, a tributary of the Uaupés (Vaupés) in the upper Negro basin, Amazonas, Brazil. The new species was collected in non-floodplain (terra firme) streams, where it occurs sympatrically and syntopically with two geographically widespread congeners, the type species of the genus, G. carapo, and G. coropinae. The new species is diagnosed by a unique combination of morphometric, meristic, and osteological traits, and by a characteristic color pattern in which the dark oblique pigment bands, diverse in shape and design, are divided into band-pairs along the length of the body, in which the band-pairs are often recurved (dorsally concave), more variable, and often reticulated in the abdominal region, and in which the pale inter-bands meet at the dorsal mid-line along most of the length of the body. Gymnotus tiquie is a member of the G. pantherinus species group, with which it shares the presence of one (vs. two) pore in the dorsolateral portion of the preopercle (except in G. pantanal and G. anguillaris), needle-shaped (vs. conical or arrowhead-shaped) teeth on the dentary and premaxilla, and a slender body (BD 5.6–10.6% HL vs. deep 8.7–13.5%, except G. chaviro, G. curupira, G. varzea, G. chimarrao, G. maculosus, G. henni, and G. inaequilabiatus that also have a slender body). Gymnotus tiquie is most similar in overall appearance to G. cataniapo of the upper Orinoco. These two species share three unique features within the G. pantherinus group: dark band-pairs with wavy irregular margins along the length of the body, a long body cavity with 45 or more pre-caudal vertebrae, and a darkly pigmented membrane in the caudal region of the anal fin.
Gymnotus tiquie, nova espécie, é descrita para o rio Tiquié, um afluente do rio Uaupés (Vaupés), bacia do alto rio Negro, Amazonas, Brasil. A nova espécie foi coletada em igarapés de terra firme, onde ela ocorre simpatricamente e sintopicamente com dois congêneres geograficamente amplamente distribuídos, a espécie-tipo do gênero, G. carapo, e G. coropinae. A nova espécie é diagnosticada por uma combinação única de caracteres morfométricos, meristicos e osteológicos, e por um padrão de colorido característico no qual as faixas oblíquas escuras, variadas em forma, são divididas em pares de bandas ao longo do corpo, nos quais os pares de bandas são frequentemente recurvados (côncavos dorsalmente), mais variáveis, e frequentemente reticulados na região abdominal, e nos quais as faixas intermediárias pálidas encontram-se na região dorsal média ao longo da maior parte do comprimento do corpo. Gymnotus tiquie é um membro do grupo de espécies G. pantherinus, com o qual compartilha a presença de um (vs. dois) poros na porção dorsolateral do pré-opérculo, dentes do dentário e pré-maxila em forma de agulha (vs. dentes do dentário e pré-maxila cônicos ou em forma de ponta de flecha) e um corpo alongado (altura do corpo 5.6–10.6% no comprimento da cabeça, vs. altura do corpo 8.7–13.5% no comprimento da cabeça exceto em G. chaviro, G. curupira, G. var
Mitochondrial (cyt b and ND2) and nuclear gene (S7 intron 1) sequences were generated to evaluate phylogenetic relationships and validity of the monotypic minnow genus Opsopoeodus. Parsimony and Bayesian phylogenetic analyses of the mitochondrial markers resulted in largely unresolved relationships among ingroup taxa. Relationships recovered from the nuclear intron were well resolved and consistent with previously published morphological, chromosomal, and behavioral data that supported the recognition of Opsopoeodus as a genus. Although mitochondrial genes recovered species as strongly supported clades, they provided limited resolution of relationships among ingroup species and genera and showed high levels of saturation at inter-genus levels of divergence. These findings re-emphasize the importance of considering multiple datasets in making taxonomic decisions and caution against use of single gene trees alone.
Substantial genetic and subtle morphological characters document that the Delta Mudsucker or chupalodo delta, Gillichthys detrususGilbert and Scofield, 1898, family Gobiidae, is a valid species separate from its widespread sister species, the Longjaw Mudsucker, G. mirabilisCooper, 1864. This species was erroneously placed in the synonymy of G. mirabilis in 1907 and has since remained unrecognized until this study. The Delta Mudsucker is restricted to a narrow zone of tidally influenced channels of the lowermost Colorado River and adjacent to the mouth of the river within its delta. It is the second fish species endemic to the river's delta in Mexico's Reserva de la Biósfera del Alto Golfo de California y Delta del Río Colorado (Upper Gulf of California and Colorado River Delta Biosphere Reserve). This study underscores the importance of continued reassessment of baseline and cryptic biodiversity, especially in habitats where initial assessment was scant prior to extensive anthropogenic influence.
Caracteres sustancial de genética y caracteres morfológicas sutiles sustentan que el chupalodo delta, Gillichthys detrususGilbert y Scofield, 1898, familia Gobiidae, es una especie válida, separada de su especie hermana de amplia distribución, el chupalodo grande, G. mirabilisCooper, 1864. Esta especie fue erróneamente colocada en la sinonimia de G. mirabilis en 1907 y ha permanecida sin reconocimiento desde entonces hasta este estudio. El chupalodo delta está restringido a una zona angosta, influenciada por la marea, de la parte más baja del delta del Río Colorado en la parte más alto del Golfo de California, y es la segunda especie de pez endémica al delta dentro de la Reserva de la Biosfera del Alto Golfo de California y Delta del Río Colorado. Este estudio subraya la importancia de la revaloración continua de la biodiversidad base y críptica, especialmente en hábitats donde la evaluación inicial fue escasa antes de una influencia antropogénica severa.
We conducted a morphometric analysis on Western Slimy Salamanders, Plethodon albagula, from each of the five mitochondrially defined groups that occur on the Edwards Plateau of central Texas. Although several groups are similar in body size and/or shape, multivariate analyses do find significant differences among groups, and several groups have clear differences for one or several characters. Thus, for several between-group comparisons, the morphological data are consistent with the mitochondrial data in arguing for cryptic lineages of slimy salamanders on the Edwards Plateau. These results demonstrate that despite the common interpretation of morphological conservatism in plethodontids, detailed morphometric studies can be used in taxonomic and evolutionary investigations of these salamanders. Lastly, male central Texas P. albagula are found to have a larger mean body size than females; this pattern of sexual size dimorphism (SSD) is reverse from that observed in nearly all other plethodontids with SSD.
Hemiergis is a distinctive limb-reduced clade of skinks of the Australian Sphenomorphus group that occur throughout much of southern Australia. Mitochondrial 12S and 16S rRNA gene-sequence data and Bayesian inference (relaxed clock and time-free models) are used to infer the phylogenetic relationships within Hemiergis, as well as test the monophyly of this clade with respect to Glaphyromorphus gracilipes, a southwestern Australia species of the polyphyletic “Glaphyromorphus” assemblage. Hemiergis monophyly is not supported by the mtDNA data, with G. gracilipes being placed as the sister lineage to H. decresiensis sensu lato. Using the Bayes factor, comparison of an alternative hypothesis of Hemiergis monophyly to the preferred hypothesis (i.e., the mtDNA inferred hypothesis with the highest posterior probability) indicates positive support (BF = 3.9–4.1) for the preferred hypothesis demonstrating Hemiergis paraphyly; thus, G. gracilipes is transferred to Hemiergis. Whereas these data strongly support the placement of the two-toed H. quadrilineatum as being closely related to the three- and four-toed populations of H. peronii, the interrelationships among these three limb-reduced phenotypes is unresolved. All other interspecific relationships within Hemiergis are weakly supported by the mtDNA. Within H. decresiensis sensu lato, there is strong support for two divergent lineages that are allopatric. The eastern lineage occurring in Victoria, New South Wales, and extreme southern Queensland is elevated to full species (=H. talbingoensis), with H. decresiensis sensu stricto restricted to the western lineage of South Australia. While many of the interspecific relationships within Hemiergis are weakly supported, these mtDNA data do very strongly favor our preferred hypothesis over an alternative phylogenetic hypothesis implied by a previously proposed parsimonious transformation series of limb reduction; this result implies more independent limb reduction events during the evolution of Hemiergis.
Three species of Scorpiodoras are recognized: S. calderonensis, S. heckelii, and S. liophysus; the latter species is described herein. Scorpiodoras calderonensis occurs in the upper Amazon basin, including the Solimões, Juruá, Japurá, and Tefé rivers. Its type locality, originally stated as “Calderón”, is elucidated as Tabatinga, Brazil. Scorpiodoras heckelii is the most widespread species, occurring in the Orinoco, Branco, Negro, and Amazonas rivers downstream of its confluence with Rio Negro. Scorpiodoras liophysus is only known from the middle Rio Madeira basin and presents a morphological feature unique within the genus: gas bladder without secondary bladder. An osteological description of the genus is provided, as well as redescriptions of S. calderonensis and S. heckelii. Additionally, a key allowing identification of the species is presented, as well as a biogeographic discussion.
Três espécies de Scorpiodoras são reconhecidas: S. calderonensis, S. heckelii, e S. liophysus, esta última descrita aqui. Scorpiodoras calderonensis ocorre na bacia do alto rio Amazonas, incluindo os rios Solimões, Juruá, Japurá, e Tefé. Sua localidade tipo, originalmente descrita como “Calderón”, é elucidada como sendo Tabatinga, Brasil. Scorpiodoras heckelii é a espécie mais amplamente distribuída, ocorrendo nos rios Orenoco, Branco, Negro, e Amazonas abaixo de sua confluência com o rio Negro. Scorpiodoras liophysus é conhecido apenas do médio rio Madeira e apresenta uma característica única no gênero: bexiga natatória sem bexiga secundária. Uma descrição osteológica do gênero é feita, assim como redescrição de S. calderonensis e S. heckelii. Adicionalmente, uma chave de identificação para as espécies do gênero e uma discussão biogeográfica são apresentadas.
We explored the effects of large magnitude flow fluctuations in rivers with dams, commonly referred to as pulsed flows, on tadpoles of the lotic-breeding Foothill Yellow-legged Frog, Rana boylii. We quantified the velocity conditions in habitats occupied by tadpoles and then conducted experiments to assess the tolerance to values at the upper limit of, and outside, the natural range. In laboratory flumes and field enclosures we mimicked the velocities observed during pulsed flows. In all experimental venues, the behavioral response of tadpoles was to seek refuge in the channel substrate when velocity increased. In a large laboratory flume, tadpoles moved freely at low water velocities (0–2 cm•s−1) and then sheltered among rocks when velocity increased. In a smaller scale laboratory flume, the median critical velocity was 20.1 cm•s−1. Critical velocity varied inversely with tadpole size, developmental stage, and proportion of time spent swimming. Velocities as low as 10 cm•s−1 caused tadpoles approaching metamorphosis to be displaced. In field mesocosm experiments, tadpoles exposed to repeated sub-critical velocity stress (5–10 cm•s−1) grew significantly less and experienced greater predation than tadpoles reared at ambient velocities. Responses to velocity manipulations were consistent among tadpoles from geographically distinct populations representing the three identified clades within R. boylii. The velocities associated with negative effects in these trials are less than typical velocity increases in near shore habitats when recreational flows for white water boating or peaking releases for hydroelectric power generation occur.
Annulus counts were compared between four sectioned levels of first dorsal-fin spines (D1–6) and anal-fin spines (A1–3) of Striped Marlin (Kajikia audax) caught in the southwest Pacific Ocean. The number of annuli observed in transverse sections varied significantly between spines of individual fish and between sections cut at varying distances along spines. Sections at levels ¼ and 1 condyle width (CW) of spines D4–6 and A3 displayed the greatest number of annuli and were not significantly different from one another. Pending validation of yearly periodicity of annulus formation, these sections could be used interchangeably in future age and growth studies on this species. The percentage of bone remodelling (vascularization) present within the central portion of fin-spine sections was negatively correlated with annulus counts. Vascularization affected the visibility of early formed annuli, which resulted in reduced counts and therefore ‘age’ estimates. Annulus counts were reduced in fin-spines D1–3, A1–2, and in sections from 2 CW and 3 CW in most spines. Statistical replacement techniques for annulus loss due to vascularization effectively nullified the differences observed between sections. This study demonstrated that annulus counts and subsequent ‘age’ estimates may vary significantly within and among calcified structures of individual fish. The risk of intra-structural variation is of particular concern to aging studies focused on species that are affected by vascularization, or where calcified structures are used indiscriminately.
The consequences of species introductions into non-native habitats are a major cause for concern in the U.S. Of particular interest are the effects of predation by introduced fishes on native amphibian communities. We sought to determine whether Foothill Yellow-legged Frog (Rana boylii) larvae could recognize non-native Smallmouth Bass (Micropterus dolomieu) as a predatory threat. Through a series of laboratory experiments, we examined the initial and overall behavioral responses of larvae to native predators (Rough-skinned newts, Taricha granulosa), introduced predators (M. dolomieu), and native non-predatory fish (Speckled Dace, Rhinichthys osculus). Each experiment examined a different potential mode of detection including chemical cues; visual cues; or a combination of chemical, visual, and mechanical cues. Initially, larvae of R. boylii responded with an increase in activity levels when exposed to visual cues of M. dolomieu. Analyses of overall responses suggested that individual larvae of R. boylii require multiple cues to facilitate predator detection. When exposed to multiple cues of their native predator, larvae responded with a significant reduction in activity levels. Those larvae exposed to cues of the non-native predator displayed similar behaviors relative to control cues. Consequently, larvae of R. boylii appear to be especially vulnerable to predation by non-native M. dolomieu.