Percina burtoni (Percidae: subgenus Percina), Blotchside Logperch, historically occupied much of the Tennessee and Cumberland River drainages, but is now restricted to highly fragmented populations where they occur at low densities. Widespread impoundment and subsequent river alteration over the past 60 years has eliminated many populations and reduced the potential for dispersal and gene flow between extant populations. We examined genetic variation at two mitochondrial genes, cytochrome b and ND2, from 74 individuals in ten populations to assess genetic population structure within P. burtoni. These data, as well as the results of recent surveys, were used to assess conservation priorities for this imperiled fish. Phylogenetic analysis recovered two well supported and highly differentiated clades within P. burtoni, one containing individuals from the Duck River drainage and a small tributary to the lower Tennessee River, and the other composed of individuals from the middle and upper Tennessee River drainage. The Duck River clade exhibits lower haplotypic and nucleotide diversity than the Tennessee River clade and shows little geographic partitioning. In contrast, most populations of middle and upper Tennessee River P. burtoni possess unique haplotypes and show strong geographic differentiation. Historical isolation of small populations in tributary systems of the upper Tennessee Basin is hypothesized to be responsible for observed patterns of differentiation within this clade. These results have implications for reintroduction programs and population augmentation with captive-reared individuals. Propagation activities should take fine-scale geographic structure into account prior to any reintroduction activities.

A new species of marsupial frog, Gastrotheca, with prominent cranial crests is described from humid montane forest on the eastern slopes of the Andes in Departamento de Pasco, Peru. The frog has an exceedingly robust cranium that most closely resembles that of G. cornuta; however, the cranial crests of G. cornuta are less well developed, and less obvious externally, than those of the new taxon. Within the genus Gastrotheca, one of the most variable parts of the skull is the squamosal, which has a variety of articular arrangements with the maxilla, the pterygoid, and in some taxa, the frontoparietal. In contrast to the modifications of dermal cranial elements, the postcranial skeleton seems to be relatively conserved in Gastrotheca.

Describimos una nueva especie de Gastrotheca de los bosques montanos de la vertiente oriental de los Andes en el Departamento de Pasco, Perú. La nueva especie se caracteriza por sus prominentes crestas craneales y por poseer un cráneo extremadamente robusto, similar al de G. cornuta; sin embargo, las crestas craneales de G. cornuta son menos evidentes extrenamente. En el género Gastrotheca, el hueso escamosal es una de las partes más variables del cráneo, teniendo una variedad de arreglos articulares con el maxilar superior, pterigoideo y, en algunos taxa, con el frontoparietal. En contraste con las modificaciones presentes en los elementos dermales del cráneo, el esqueleto postcraneal parece ser relativamente homogéneo en Gastrotheca.

We report food habits of River Darters (Percina shumardi) in Brushy Creek and the Sipsey Fork Black Warrior River, Alabama. River Darters preyed heavily on pleurocerid snails in both streams. Snail feeding varied widely among sample dates and was highest in October when snails represented nearly 100% of darter food items. Snail feeding declined through the spring, nearly ceasing by May, but increased to high levels again in July when hatchling snails composed about 80% of darter food items. Mean and maximum size of snails eaten increased with darter size, but minimum snail size was not related to darter size, indicating a broadening of prey size for larger darters. Non-snail food items were dominated by chironomid, trichopteran, and ephemeropteran insect larvae; these food items were most commonly eaten during periods of low snail feeding or feeding on hatchling snails. Specialization for snail feeding is suggested for all species in the subgenus Imostoma, including P. shumardi, but this feeding habit is well documented previously only for P. tanasi. Published diet studies for other species of Imostoma, including populations of P. shumardi from elsewhere in its range, did not document snail feeding; most other observations of snail feeding for the group are anecdotal. Few other darters or other fish species are documented to prey heavily on riverine snails. Although the limited amount of published information makes it difficult to assess the degree to which Imostoma as a group relies on snails as a food source, P. shumardi and P. tanasi represent two of the few native fishes that exploit the abundant and diverse pleurocerid snail fauna of eastern North America.

A new species of the genus Jenynsia from southern Brazil is described. The analyses of character states, primarily osteological, support the new species as belonging to the subgenus Plesiojenynsia. A new hypothesis of phylogenetic relationships for the genus, including the new taxon, is presented. The new species, from the Rio Iguaçu drainage in the Brazilian state of Paraná, is diagnosed by the following combination of characters: absence of mandibular canal pore W, long epiotic processes in adults, ten anal-fin rays, discontinuous midlateral and dorsolateral stripes formed by series of blotches on body, midlateral stripe discontinuous anterior to dorsal-fin origin, large third hypobranchial, and presence of teeth on fourth ceratobranchial of adults.

Uma nova espécie do gênero Jenynsia do sul do Brasil é descrita. As análises de estados de caracteres, principalmente osteológicos, suportam a nova espécie como pertencente ao subgênero Plesiojenynsia. Apresenta-se uma nova hipótese de relações filogenéticas para o gênero, incluindo o novo táxon. A nova espécie, da bacia do Rio Iguaçu no Estado do Paraná, é diagnosticada pela seguinte combinação de caracteres: ausência do poro W do canal mandibular; processos epióticos longos nos adultos, dez raios na nadadeira anal; faixas dorso-lateral e mediano-lateral descontínuas e formadas por uma série de máculas nos flancos; faixa mediano-lateral descontínua anterior a origem da nadadeira dorsal; terceiro hipobranquial grande; e presença de dentes no quarto ceratobranquial dos adultos.

A molecular phylogeny based on a fragment of the mitochondrial 16 S rRNA gene and morphological comparisons suggests that only one polymorphic species of large Dendrobates, commonly assigned to D. tinctorius, occurs on the eastern Guiana Shield and its vicinities. The oldest available name for this taxon is D. tinctorius (Schneider, 1799). We place D. azureus Hoogmoed, 1969 as its junior synonym. Data for D. machadoi Bokermann, 1958 are not available, but we suspect that this name has to be treated in the same way. Dendrobates tinctorius exhibits numerous variants differing in color and pattern.

Knodus tiquiensis, new species, is described from Rio Tiquié, a tributary of the Rio Uaupés, upper Rio Negro system, Amazon basin, Brazil. The new species is distinguished from its congeners by the presence of thickened skin forming folds that cover the basal portion of the six anteriormost branched anal-fin rays and its interradial membrane. Also, the anteriormost six anal-fin rays are considerably thicker than remaining rays of the fin. Comparisons to Knodus tiquiensis with its congeners are presented based on an examination of type material of all species currently included in the genus.

Knodus tiquiensis, espécie nova, é descrita do Rio Tiquié, um tributário do Rio Uaupés, alto Rio Negro, Amazonas, Brasil. A nova espécie pode ser distinguida de suas congêneres pela presença de uma pele espessada entre os raios anteriores da nadadeira anal, formando dobras mais desenvolvidas na base e membranas inter-radiais dos seis primeiros raios ramificados e por possuir tais raios consideravelmente mais espessos que os demais. Comparações entre Knodus tiquiensis com seus congêneres são apresentadas, baseadas em exame do material tipo de todas as espécies atualmente incluídas no gênero Knodus.

Amphibian populations comprise a large fraction of vertebrate biomass in many freshwater and terrestrial ecosystems where they produce organic matter in the form of egg clutches and carcasses. A lack of quantitative information on the decomposition of these materials for any species precludes an accurate assessment of energy and nutrient fluxes from amphibians to detrital food webs and comparisons among taxa and systems. We estimated decay rates (−k) of Spotted Salamander (Ambystoma maculatum) egg clutches and larval and adult carcasses, and then used this information to estimate C and N fluxes associated with ambystomatid assemblages in breeding ponds. We found that all life stages represent a high quality source of organic matter (range C∶N  =  3.7∶1–5.3∶1) in aquatic and terrestrial habitats, particularly in ponds where egg clutches and larvae are seasonally abundant. Decay rates for egg clutches (−k  =  0.075 d⁻¹), larval carcasses (−k  =  0.758 d⁻¹), and adult carcasses (−k  =  0.062 d⁻¹) were more rapid compared to published estimates for other types of animal matter in similar habitats and were much more rapid than estimates for detritus of dominant species of vegetation found in breeding ponds and adjacent forest in southern Illinois. For five regional breeding ponds, we estimated that mortality of larval A. maculatum provided a flux to detrital food webs ranging from 34.6–165.1 mg C m⁻² d⁻¹ and 6.6–31.5 mg N m⁻² d⁻¹ during decomposition; fluxes associated with egg clutches ranged from 38.8–895.0 mg C m⁻² d⁻¹ and 10.4–239.3 mg N m⁻² d⁻¹. Our study suggests that ambystomatid salamanders seasonally provide appreciable inputs of labile materials to detrital food webs and facilitate the rapid recycling of energy and materials within breeding ponds and between ponds and adjacent forest.

Slender-bodied, diurnal “sand snakes” of the genus Psammophis are widespread and abundant through Africa, but the general biology of these animals remains poorly known. For example, sexual dimorphism is unstudied because it is difficult to determine the sex of live specimens (uniquely among snakes, the male hemipenis is vestigial). Our dissections of 700 preserved specimens provide detailed ecological information on ten psammophiine species from southern Africa. Males grow larger than females in most taxa, especially in species of large absolute body size. However, sex differences in body proportions (relative head size, relative tail length) are minor. Females produce small clutches (generally <10 eggs), with larger clutches in larger females in some but not all species. Psammophylax tritaeniatus differs from the nine Psammophis species studied in its higher fecundity and its primary reliance on mammalian rather than reptilian prey. Within Psammophis, five species (P. brevirostris, P. jallae, P. leopardinus, P. subtaeniatus, P. trigrammus) fed mostly on scincid lizards, two (P. namibensis, P. notostictus) fed mostly on lacertid lizards, and two (P. trinasalis, P. mossambicus) took approximately equal numbers of lizards and mammals. Although dietary composition thus varied with snake species and body size, conspecific males and females took similar prey types. Thus, despite reports of unusual mating systems in captive psammophiines, these snakes exhibit only minor sexual dimorphism in size, bodily proportions, and dietary habits.

A new species of Brachyhypopomus from north and northeast Uruguay is described. The new species is found in tributaries of the Uruguay River and southern Los Patos-Merín system. Brachyhypopomus bombilla can be distinguished from all other species of the genus by the following combination of characters: pigmentation pattern of body consisting of scattered dark brown pigmentation over a brown background, more dense on the dorsal half of the body, epidermal laterosensory canals not depigmented, head depth 61.8–76.4% of HL, caudal filament 6.5–16.6% of TL, anal-fin rays 155–190, fourth supraorbital pore dorsal and halfway between posterior nares and anterior margin of orbit, upper jaw slightly longer than lower jaw, mesocoracoid bone not ossified, maxilla anterodorsal process slender, all branchiostegal rays of equal size, none hook-like. Like many other species of the genus Brachyhypopomus, B. bombilla generates a pulse-type biphasic EOD, with a head-positive phase followed by a head-negative phase. The EOD duration of the new species was significantly lower than the EOD duration of the sympatric B. pinnicaudatus, whereas the EOD rate was significantly higher, thus suggesting that duration and frequency are conspicuous electrophysiological parameters that greatly aid in the description of electric fish species.

We describe a new species of high-elevation rainforest tree frog (genus Platymantis) from the Nakanai Mountains, New Britain Island, Bismarck Archipelago, Southwestern Pacific. The new species is characterized by moderate body size (34.2–35.8 mm for four males), widely expanded terminal digital disks of the fingers and toes, smooth skin of the dorsum, a distinctive color pattern, and a complex, amplitude-modulated advertisement call produced in groups of 3–6 notes. We compare the new species to all known species of Platymantis from New Britain and to additional phenotypically similar species from the Solomon Islands and Fiji. It is most similar to P. nexipus, a species known previously from only a single specimen. We rediagnose and redescribe P. nexipus on the basis of the holotype and ten recently collected specimens, provide the first descriptions of the advertisement calls of both species, and comment on an additional suspected undescribed species from the Nakanai Mountains of New Britain Island.

Persistence of direct contacts among species has important implications for the potential of taxa to influence each other's traits or evolutionary trajectories. We examined persistence of species (or “ecospecies”) associations in Brier Creek, Oklahoma, based on visual surveys on seven dates 1982–1983 and on 12 dates 1995–2003 in 14 contiguous pools. Fishes were considered to be associated, in direct contact, if they occurred within the same pool during a survey. Mantel tests showed that associations among 11 common taxa from survey to survey were highly variable, but were significantly concordant across 11 of 18 intervals between surveys. Most floods and droughts were not followed by decreased concordance of associations, but associations did change after the second of two very severe droughts (1998 and 2000). Within-year associations were highly concordant in 1983 and in 1996, years with the most repeated surveys. Patterns of association were highly concordant across years for surveys in late summer and episodically concordant for surveys in May 1995–2003, but not in autumn. A cluster analysis comparing all surveys showed that associations among taxa differed between earlier (1982–83) and later (1995–2003) surveys. For some subsets of taxa, we found strong, consistent association across most surveys.

As a result of our recent herpetological surveys conducted in Madagascar, important new collections of large occipital-lobed Calumma chameleons have been made. These collections allow the recognition of six new Calumma species, in addition to the six currently recognized species. Five of the new species were located at specific montane regions, and one is broadly distributed in mid-altitude forest within the interior of the island. As previously reported for Brookesia dwarf chameleons, species richness in this Calumma group is greatest in northern Madagascar. An identification key is given for all 12 species and a new description provided for Calumma brevicorne, a species that has been confused with several other species. Previously described taxonomic uncertainties associated with this species are resolved, including the problematic status of the Calumma brevicorne tsarafidyi holotype, which we consider to represent the nominate form and unlikely to have been collected at Tsarafidy. Sexual dimorphism (including hemipenis development), biogeography, and conservation issues are also discussed for the group. The Bemanevika Lakes region of Southwest Tsaratanana harbors a new Calumma species not currently recorded for any protected area, and forest of this region is suggested for inclusion within a future reserve.

Behavioral observations have suggested that Channel Catfish, Ictalurus punctatus, spawn as monogamous pairs and that males alone provide subsequent care to the resulting embryos and fry. However, genetic monogamy is quite uncommon in fish and is not necessarily correctly predicted by apparent social interactions. Here we develop and employ seven microsatellite loci to address biological parentage and the genetic mating system in a natural population of I. punctatus. A total of 175 progeny and their respective attendant males were genotyped from five nests. Results indicate that each male had mated with only one female in his nest. Additionally, one nest contained a second group of full sibs unrelated to the attendant male and his mate who proved to be the biological parents of all other progeny within that nest. This instance probably represents either a case of nest piracy by the attendant male or perhaps our inadvertent sampling of progeny from two closely adjacent nests. In any event, our findings help confirm a rare suspected example of genetic monogamy in a fish species with uniparental offspring care.

Using radio telemetry and geographic information systems (GIS), we investigated movement patterns, home ranges, and habitat selection by Eastern Massasauga rattlesnakes from 2003 to 2004 at an 815-ha fen preserve located in southeastern Michigan, USA. We tested habitat selection on three different scales: microhabitat (by modeling differences in climatic and structural variables between snake-selected sites and random sites, using logistic regression), macrohabitat, and landscape-scale (both by compositional analysis comparing proportions of habitat types used versus proportions available). One hundred percent minimum convex polygon (MCP) home ranges averaged 1.3 ha, and daily movement rates averaged 6.9 m/d. Models predicted that snakes exhibit complex microhabitat selection based on multiple climatic and structural variables including soil temperatures, relative humidity, canopy cover, litter depth, and various vegetation parameters. Snakes actively establish home ranges in the broader landscape by selecting areas with disproportionate quantities of emergent wetland, scrub/shrub wetland, and lowland hardwood habitats. Upland hardwood and all human-altered landscapes were rarely used, even though they were available. This has potentially serious conservation implications. Encroachment of these types of landscapes into areas of suitable habitat could severely restrict movement and home range sizes of these snakes. Potential disruption of movement patterns and gene flow of remaining populations could be extremely detrimental to this species.

A new species of nototheniid fish, Cryothenia amphitreta, is described from a single gravid female collected in mid-November 2004 by divers in McMurdo Sound in the Ross Sea region of Antarctica. The new species closely resembles the only known congener, C. peninsulae, collected off the west coast of the Antarctic Peninsula, but differs substantially in pelvic-fin length (13.4 vs. 19.3–24.4% SL), total vertebrae (57 vs. 50–53), body size at maturity (261 vs. 100–144 mm), and interorbital-pit morphology. The neutrally-buoyant C. amphitreta is characterized by a wide, well-defined interorbital pit divided by a raised medial ridge, scales anterior to this depression in the interorbital region, and a dark pigmentation of the mouth, gill, and body cavity linings. This species is protected against freezing by high levels of antifreeze proteins in its body fluids. Phylogenetic reconstruction using the mitochondrial NADH dehydrogenase subunit 2 (mtND2) suggests that C. amphitreta falls within the current designation of the nototheniid subfamily Trematominae.

Texas populations of slimy salamanders are isolated from other members of the Plethodon glutinosus complex and are currently placed in the species P. albagula with populations from the Ozark Plateau and Ouachita Mountains of Missouri, Oklahoma, and Arkansas. We sequenced a portion of the mitochondrial protein-coding gene ND4 for 52 P. albagula from 25 localities in Texas and one locality in Missouri. Bayesian MCMC analysis identified five parapatric lineages of Plethodon in Texas. Several morphologically distinctive populations are phylogenetically embedded within the Texas radiation. Additional studies of the interactions among the lineages identified in this study will be necessary to resolve their taxonomic status.

Most studies that have investigated the influence of hydric conditions during incubation on the size and quality of hatchling reptiles have used either vermiculite or sand as the incubation medium, and the applicability of data derived from eggs using one media type or the other to natural populations has had considerable debate. However, few studies have used soil from actual nesting areas as the incubation medium. In this study, I tested the influence of variation in substrate water content during incubation on the size of hatchling Snapping Turtles from southeastern Michigan using soil collected from actual Snapping Turtle nests. Eggs from six clutches were fully buried in sterilized soil that had been dried and then reconstituted to six different levels of hydration (3, 5, 7, 9, 11, and 13% gravimetric water content). Eggs in the driest soil (3%) had a slight net loss of mass over the course of incubation, whereas eggs in the wetter soils gained mass to varying degrees correlating positively with soil water content. Hatchling mass was significantly lower in the two driest soils than in the wetter soils. Carapace length was significantly shorter for hatchlings from the driest soil (3%) than for those from soils with 7% and 9% water contents, and significantly shorter for hatchlings from the wettest soil (13%) than for those from the 7, 9, and 11% water contents. Soil water contents measured adjacent to a single nest site over three consecutive field seasons ranged from 1.1 to 8.2%, with median water contents ≤ 5% in all three seasons. These findings support the hypothesis that normal variation in soil hydration can influence the size of hatchlings emerging from natural nests. The degree to which hatchling size varies with normal variation in soil water content, however, may have only minor impact on hatchling survivorship in light of other factors that could potentially influence hatchling survival in this species.

Nucleotide and amino acid sequence data from a 544-bp segment of the mitochondrial cytochrome B (Cytb) gene were used to examine phylogenetic relationships of the Shafted Bonefish, Albula ( = Dixonina) nemoptera, a morphologically distinct bonefish limited to the coastal waters of the eastern Pacific and western Atlantic, among members of the widely distributed and cryptic A. vulpes species complex of Albula (Albuliformes: Albulidae). Phylogenetic trees based on Bayesian and parsimony methods indicated that A. nemoptera from the tropical eastern Pacific (Colima, México) nested within the A. vulpes complex, supporting the placement of the genus Dixonina Fowler, 1911 into the synonymy of Albula Scopoli, 1777. Phylogenetic analyses also showed that A. nemoptera is the sister taxon to the undescribed Albula sp. E from the western Atlantic (Bahia, Brazil), previously placed in the A. vulpes complex. This evidence, together with the presence of a diagnostic amino acid substitution in the translated Cytb segment in both species, suggested that Albula sp. E, identified solely from molecular data with no adult voucher available, should be provisionally assigned to A. nemoptera.

Secuencias de nucleótidos y aminoácidos que provinieron de un segmento de 544 bp del gen citocromo B (Cytb) de las mitocondrias fueron utilizadas para analizar las relaciones filogenéticas del macabí de hebra Albula ( = Dixonina) nemoptera, un macabí morfológicamente distinto que habita las aguas costeras del océano Pacifico Oriental y el Atlántico Occidental, con las especies crípticas del complejo A. vulpes del género Albula (Albuliformes: Albulidae) que tienen una amplia distribución. Dos clases de árboles filogenéticos estaban de acuerdo y demostraron que el A. nemoptera del Pacifico Oriental Tropical (Colima, México) se agruparon con las especies del complejo A. vulpes, apoyando la conclusión de que el género Dixonina Fowler, 1911 debería ser considerado un sinónimo del género Albula Scopoli, 1777. Los análisis filogenéticos también demostraron que la especie hermana a la A. nemoptera es la especie no identificada Albula sp. E del Atlántico Occidental (Bahía, Brasil) que previamente fue colocada en el complejo A. vulpes. Esta evidencia, así como la presencia de una sustitución diagnóstica de un aminoácido en la proteina de citocromo B en ambas especies, sugirieron que el Albula sp. E, que fue descrito utilizando solamente datos moleculares sin especimenes completos, debería ser asignado provisionalmente a la especie A. nemoptera.

We present morphological evidence that supports the placement of “Hyla” chlorostea Reynolds and Foster, 1992 (previously of uncertain affinities) in the Hyloscirtus armatus group. Also we continue to recognize it as a valid species, pending a revision of populations currently associated with the name Hyloscirtus armatus. Furthermore, we report the presence of a mental gland in adult males of the H. armatus group. Given that the presence of a mental gland is the only putative synapomorphy for the Hyloscirtus bogotensis group, its presence in the H. armatus group raises concerns about the monophyly of the former group.

Stlegicottus xenogrammus Bolin, 1936, was described from a single small, deteriorated specimen from the southern Bering Sea. No subsequent specimens have been identified. Comparison with the holotype of Rastrinus scutiger confirms that the two specimens represent the same species, and previously reported differences between the two are likely the result of the small size and deteriorated condition of the holotype of S. xenogrammus. Because Stlegicottus xenogrammus cannot be distinguished from Rastrinus scutiger by any reliable character, the two names are treated as synonyms, with R. scutiger having priority, and Stlegicottus becomes a junior synonym of Rastrinus.

Kernel home-range estimators are becoming more widely used to determine the home-range size for herpetofauna, despite the problems associated with selecting the appropriate smoothing factor. We used simulations to demonstrate the inconsistency of kernel estimators at determining the home-range size of random distributions. Furthermore, we used the positions of ten adult male Lampropeltis triangulum radio-tracked over two full active seasons (2003 and 2004) to demonstrate that the size of the home range increases significantly with an increase in the smoothing factor. The degree of increase, however, was not consistent between individuals. In addition, using least-squares cross-validation to select the smoothing factor produced a wide range of values for different individuals. Because of these inconsistencies, we suggest using the minimum convex polygon (MCP) method to calculate home-range size in studies of herpetofauna. When studying habitat use, however, we suggest using the MCP as the area of the home range and adjusting the smoothing factor until the area of the 95% kernel equals the area of the MCP. This provides an objective method for selecting the smoothing factor.

Caudal autotomy is widely employed by lizards to facilitate escape from predators. Despite conferring immediate short-term benefits, tail loss may involve substantial costs, including impaired locomotor performance, loss of energy reserves, and reduced survival during subsequent encounters with predators. We investigated whether tail autotomy influenced the running speeds and anti-predator behaviors of adult male Velvet Geckos, Oedura lesueurii. This nocturnal terrestrial gecko displays a range of anti-predator behaviors (tail waving and vibration, slow movement, and crypsis) in the presence of scent from the predatory Broad-headed Snake, Hoplocephalus bungaroides. Since tailless geckos cannot use tail displays to attract predatory strikes away from the torso, we hypothesized that tailless geckos would spend more time motionless in the presence of Broad-headed Snake scent. Sprint speeds of tailless and tailed Velvet Geckos were very similar over short (0.25 m) and longer distances (1 m). During locomotor trials, geckos frequently stopped along the racetrack, but tail autotomy did not affect the frequency of this behavior. Contrary to our predictions, tailless Velvet Geckos did not decrease their activity levels in the presence of Broad-headed Snake scent. Overall, our data support the hypothesis that the locomotor costs associated with tail autotomy are relatively minor in lizard species where the tail plays no functional role in locomotion.

Recent studies suggest that the incidence of morphological abnormalities has increased in many amphibian populations, often exceeding the estimated background deformity frequency of 0–5%. Many chemical contaminants, including agrochemicals, can cause abnormalities in amphibians, but data on the occurrence of morphological abnormalities in wild amphibian populations in Europe is anecdotal at best. In a large-scale study covering 264 ha and 26 farmland breeding populations of the Common frog (Rana temporaria) in southern Finland, we investigated whether the incidence of morphological abnormalities in metamorphs differed from the background level of 0–5% and among populations along an agrochemical gradient. Abnormalities occurred in a low frequency (1% of the studied individuals; 40/4115), the highest population-specific frequency being 4%. We found no evidence for increased abnormality frequencies in the habitats most likely exposed to agrochemicals. Hence, the data suggest that current Finnish agrochemical practices are not causing increased incidences of morphological abnormalities in Common frog populations breeding in farmland areas.

For over a century, hypotheses regarding the primary functional utility of snake venoms have been debated in literature. Researchers have speculated that the development of venom delivery systems has been a key innovation leading to the evolutionary radiation of venomous snakes over the past 25–30 million years. Interestingly, little is known about the energetic requirements involved in producing venoms in these animals. Here I examined the metabolic cost associated with venom production in three species of North American pitvipers. Immediately following venom extraction, snakes demonstrated an 11% increase in resting metabolic rates during the first 72 h of venom replenishment; this metabolic increase was apparently a result of metabolic costs involved with venom production and was an order of magnitude greater than that predicted for producing an identical mass of mixed body growth. Extracted liquid venom yield of snakes was allometrically correlated with snake body mass (4.77W^0.60) and had mean moisture content of 70.9%. Venom yields (wet or dry) were not correlated with the magnitude of the metabolic increase measured during the first 72 h of venom replenishment, suggesting the cost of venom replenishment is independent of extracted mass. The significant post-extraction metabolic increases measured in these snakes support existing hypotheses about the metabolic cost of venom production and may help explain why these animals meter their venom conservatively.

Here we document sexual dimorphism in both external measurements of the head and discrete features of the skull in Apteronotus bonapartii. To quantify morphological variation in A. bonapartii, ten external morphometric measurements were taken from the head and body of 58 individuals. By using Discriminant Function Analysis, we found that the best predictors for distinguishing sexes are the body depth, snout length, and the distance from the tip of the lower jaw to rictus (i.e., the gape length). Two measurements showed significant differences between males and females: supraoccipital to base of dorsal thong and tip of the lower jaw to rictus. Most skeletal elements were found to be similar between males and females; however, in males some elements of the skull roof (e.g., frontal) and suspensorium (e.g., endopterygoid) are elongate relative to females, and the lateral ethmoid is more obliquely positioned. In females, the dentary and anguloarticular are relatively deep and come together in a sharp angle dorsally, giving the lower jaw an almost triangular shape; in males the dorsal margin of the lower jaw is smoothly arched.

No presente trabalho nós documentamos o dimorfismo sexual em Apteronotus bonapartii utilizando medidas externas e características do crânio. Para quantificar a variação morfológica em A. bonapartii, dez medidas morfométricas foram obtidas da cabeça e corpo de 58 indivíduos. Através da Análise de Função Discriminante, os melhores preditores para distinguir machos e fêmeas foram a altura da cavidade abdominal, comprimento do focinho, e distância da mandíbula ao rictus. Na Análise de Covariância, duas medidas mostraram diferenças significativas entre machos e fêmeas: a altura do corpo na base do supraoccipital e mandíbula ao rictus. A maioria dos elementos do crânio dos machos e fêmeas são similares. Entretanto, em machos alguns elementos do crânio (e.g., frontal) e suspensório (e.g., endopterigóide) são alongados, em comparação com as fêmeas. Em machos, o etmóide lateral é posicionado mais oblíquamente do que nas fêmeas. Em fêmeas o dentário e o ânguloarticular têm maior altura e proporcionam uma forma quase triangular na porção anterior da mandíbula, onde em machos a margem dorsal da mandíbula é levemente arqueada.