bluuebunny/crossref_metadata_2025_split huggingface dataset:
Phylogenetic relationships of the African egg-eating snake Dasypeltis scabra
Authors: Lopez T.J. , Maxson L.R. , Dowling H.G. 
Published: April 2008

AbstractThe unusual morphological adaptations associated with specialization on a diet of eggs have been used as evidence to justify familial or subfamilial status for the egg-eating snakes, including the African genus Dasypeltis. We evaluate the phylogenetic relationships of Dasypeltis scabra by comparing albumin evolution in Dasypeltis and available representative colubrine taxa using the quantitative immunological technique of micro-complement fixation. We find that Dasypeltis scabra is included among a large colubrine assemblage containing racers (Coluber, Masticophis, Spalerosophis, and Ptyas), the ratsnake Elaphe, and the kingsnake Lampropeltis. Further, these data suggest that Dasypeltis is genetically most similar to some members of a racer lineage and arose from an ancestral colubrine stock as early as ten million years ago.
The internal oral morphology of some anuran larvae from south India: a scanning electron microscopic study
Authors: Das Indraneil 
Published: April 2008

AbstractThe internal oral morphology of the larvae of four species of sympatric anuran amphibians from a locality in south India was examined by scanning electron microscopy. A close fit between diet and oral structures was found. The mouthparts are considerated as adaptive for a variety of feeding modes, including filter-feeding, algal-scraping and macrophyte-snipping.
Biomechanical reasons for bipedalism in reptiles
Authors: Christian A. , Horn H.-G. , Preuschoft H. 
Published: April 2008

Abstract
Bipedal locomotion can be observed in numerous species of recent tetrapodal reptiles which usually have well developed tails and hindlimbs while the forelimbs are considerably shorter and weaker than the hindlimbs. It is commonly used when the reptiles move at the highest possible speeds of locomotion. The different development of the extremities is a common feature among recent reptiles that can be understood as an adaptation to quick acceleration. Additionally it reduces the interference of fore-and hindlimbs at high speeds. We present some biomechanical arguments to show how and why bipedalism can facilitate quick running in recent reptiles in which the hindlimbs are much longer and stronger than the forelimbs. Our main arguments can also be applied to some dinosaurs.
Courtship behaviour of the salamander Desmognathus imitator (Amphibia: Caudata: Plethodontidae)
Authors: Verrell Paul A. 
Published: April 2008

AbstractCourtship in the imitator salamander, Desmognathus imitator, follows a predictable course that appears characteristic for the genus. Three more-or-less consecutive phases are recognized: orientation of the male to the female, persuasion of the female by the male (involving both tactile and chemical stimuli) and indirect sperm transfer by means of a spermatophore. The individual behaviour patterns that comprise courtship in D. imitator are similar to those observed for congeneric species of similar body size, except for "bite-and-seize", which has previously been described only in two dwarf species. Understanding the evolution of courtship in the genus Desmognathus will be greatly facilitated when behavioural characters in all taxa can be optimized onto an independent phylogenetic tree.
Spontaneous haploid-triploid mosaicism in the progeny of a Rana kI. esculenta female and Rana lessonae males
Authors: Berger Leszek , Ogielska Maria 
Published: April 2008

AbstractA female Rana kl. esculenta was crossed with three different R. lessonae males. Three froglets with unexpected phenotypes appeared. Two of them were chimerae with one side of the body of lessonae, and the other of escutenta phenotype, and one displayed lessonae, instead of the expected esculenta, phenotype. Blood of three individuals was composed of small haploid and large triploid erythrocytes. These results indicate that the froglets were 1n/3n mosaics.
Dynamics of predation in Lacertidae: the relation between locomotor pattern and prey-capture probability in three contrasted species
Authors: Avery Roger , Tosini Gianluca 
Published: April 2008

AbstractThe probability that lizards would capture crickets declined with distance from the snout, at rates which were significantly more rapid in all directions in Lacerta vivipara than in Podarcis muralis or L. viridis, i.e. the former species responded to potential prey over a smaller area. Capture probabilities at any distance in front of or behind the snout were lower in P. muralis or L. viridis which were pausing during locomotion than in basking lizards, confirming previous results with L. vivipara. Using capture probabilities for pausing lizards to calculate the average time it would take to find a single item of prey (tf) in relation to the mean length of locomotor bursts, on the assumption that prey could only be detected while a lizard was pausing, showed that actual mean burst distance corresponded exactly with the burst distances which gave rise to minimum tf in L. vivipara. Mean locomotor burst distances in P. muralis and L. viridis were lower than the distances which gave minimum tf values. It is suggested that, in these species, the mean burst length has evolved as a compromise between minimising tf and avoiding the high overall energy expenditures which would result from long burst lengths.
The systematic status of the Ramphotyphlops flaviventer (Peters) complex (Serpentes: Typhlopidae)
Authors: Wallach V. 
Published: April 2008

AbstractAn examination of the type specimens of Typhlops aluensis Boulenger, T. buehleri Hediger, T. depressus Peters, T. flaviventer Peters, T. philococos Wemer, T similis Brongersma, and T. supranasalis Brongersma, in conjunction with external and internal morphology, indicates that Ramphotyphlops flaviventer (sensu McDowell) consists of two easily recognizable allopatric populations here considered as valid species, a western one referred to R. flaviventer and an eastern one referred to R. depressus. Two additional taxa (R. similis and R. supranasalis), closely related to R. flaviventer, appear to deserve recognition. Ramphotyphlops similis is distinct from R. flaviventer in external morphology and thus elevated to full species status. The status of R. supranasalis is debatable but it is provisionally treated as a full species based upon discrete supranasals and an insular distribution. A taxonomic synopsis and preliminary identification key to the Ramphotyphlops flaviventer complex are provided.
The reproductive cycles of the oviparous lizards
Authors: van Wyk J.H. , Mouton P. le F.N. 
Published: April 2008

Abstract
We examined the reproductive cycles of two species of the only oviparous genus Platysaurus in the predominantly viviparous family Cordylidae, endemic to Southern Africa. The reproductive cycles of Platysaurus capensis and P. minor were determined using data obtained from field caught and museum specimens. Males of both species exhibit testicular recrudescence during autumn (April-May) and maximum testicular volumes together with peak spermiogenic activity occur during winter through early summer (July-November). Small testicular volumes associated with testicular regression occur during mid-summer (December) through early autumn (March). Similarly, females of both species begin vitellogenesis in autumn, culminating in ovulation during spring (September-October). Females are ovigerous in summer (November through December). Clutch size is fixed on two eggs. In both species, male and female cycles are well synchronised. The fact that the autumn/winter ovarian cycles of these oviparous lizards correspond to that of viviparous members of the family Cordylidae adds to the data that suggest that the oviparous mode of reproduction in the genus Platysaurus represents one of the few known cases of an evolutionary reversal from the derived viviparous mode. Along with the viviparity-oviparity reversal a postnuptial-prenuptial testicular cycle reversal is suggested. Data presented in this paper support the hypothesis that the ancestral oviparous Platysaurus evolved on the Mozambique lowlands from a viviparous montane Pseudocordylus ancestor.
The effect of temperature on calling energetics of the spring peeper (Pseudacris crucifer)
Authors: Wells Kentwood D. , Taigen Theodore L. , O'Brien Jennifer A. 
Published: April 2008

Abstract
Oxygen consumption of calling male spring peepers (Pseudacris crucifer) was measured at five temperatures (7, 10, 15, 19, and 23°C) encompassing the natural range of variation encountered during the breeding season. Oxygen consumption increased as a linear function of calling rate, which in turn was a linear function of temperature. Hence, nearly all the increased cost of calling at warmer temperatures was accounted for by increases in calling rate; temperature did not appear to have any independent effect on activity metabolism. During one breeding season, ambient temperature increased throughout the season, resulting in an hourly cost of calling at the end of the season that was double the cost at the beginning. Periodic warm spells also resulted in major increases in the cost of calling.
Battles for mates and food: Intraspecific combat in island tigersnakes (Notechis ater) from southern Australia
Authors: Firmage M. , Shine R. 
Published: April 2008

Abstract
Male-male combat occurs in mainland populations of tigersnakes (Notechis scutatus), but authorities have disagreed as to whether or not this behaviour also occurs in island tigersnakes (Notechis ater). In this paper, we confirm that intraspecific combat frequently occurs between island tigersnakes maintained in captivity. Two different kinds of combat bouts were observed. We interpret the first type (ritualised "wrestling" matches between large adult males) as a reflection of sexual competition. This behaviour was seen in snakes from each of the island populations investigated, including Tasmania. Agonistic behaviour was exhibited by females and juveniles as well as by adult males: however, this second type of combat was always initiated by the introduction of food items to the enclosure, and incorporated vigorous biting as well as (or instead of) wrestling. Further observations, in the field as well as in captivity, are needed before we can interpret the functional significance of this behaviour. The food-induced combat may be an artifact of high densities of captive snakes, or alternatively may be exhibited in the wild also. We speculate that the high abundance of tigersnakes on some islands, and the highly clumped nature of prey resources (e.g. muttonbird chicks) in both space and time, may have favoured direct interference competition for prey items between island tigersnakes. If so, some elements of the social system of island tigersnakes may resemble the condition seen in many lizard species, rather than in other snakes.
Reproductive ecology of Bombina variegata: characterisation of spawning ponds
Authors: Barandun Jonas , Reyer Heinz-Ulrich 
Published: April 2008

Abstract
The use of spawning sites by Bombina variegata was analysed in a dynamic habitat containing a variety of different ponds. Cool or shadowy as well as permanent ponds were not used for spawning at all. Among the ephemeral ponds that were used, egg numbers increased with water temperature, both when compared among ponds and between different areas within ponds. Egg numbers were also higher in ponds of intermediate duration than in those persisting for shorter or longer periods. Ponds of intermediate duration with moderate predator densities and with larvae of competing anuran species (Hyla arborea, Bufo calamita) were used more often than short-lived ponds with no predators and competitors. This pattern of spawn deposition can be interpreted as an attempt to select sites allowing rapid larval development (warm water) and to avoid sites with high numbers of newts and invertebrate predators (permanent ponds). The selection critera seem to be adaptive, because pond duration and desiccation are more important for larval survival than predators and competitors. Yet, optimal reproductive conditions remain highly unpredictable for Bombina variegata, as the characteristics and dynamics of spawning ponds are mainly determined by climatic conditions. Consequently, survival chances of tadpoles can change within a few days or weeks, depending on rainfall and evaporation.
Evaporative water loss of Australian goannas
Authors: Thompson G.G. , Withers P.C. 
Published: April 2008

AbstractThe common intra-specific mass exponent for the standard evaporative water loss was 0.86 for nine species of goanna (V. gilleni, V. caudolineatus, V. brevicauda, V. eremius, V. acanthurus, V. tristis, V. gouldii, V. rosenbergi and V. panoptes). The inter-specific mass exponent for evaporative water loss (EWL) was 0.95; EWL (mg h-1) = 2.149M0.95 The overall resistance to water loss was significantly lower inter-specifically for larger species than smaller species; however, there was no significant intra-specific relationship between resistance and body mass. The evaporative water loss of arboreal goannas (V caudolineatus, V gilleni and V. tristis) was less than that of terrestrial goannas (V brevicauda, V eremius, V acanthurus, V. gouldii, V rosenbergi and V. panoptes); this presumably reflects the exposure of these arboreal goannas to higher wind velocity and drier air. The more mesic V. rosenbergi had a higher evaporative water loss than the more arid species.
The tadpole of Pseudis minuta (Anura: Pseudidae), an apparent case of heterochrony
Authors: de Sá Rafael O. , Lavilla Esteban O. 
Published: April 2008

AbstractThe external morphology, oral disc, and coloration pattern of the larva of Pseudis minuta are described. Tadpoles are mostly bottom dwellers that have a small, terminal oral disc with a labial tooth row formula 1(1-1)/(1-1)2. Internal oral anatomy is characterized using scanning electron microscopy, representing the only description available for the family Pseudidae. The coloration pattern of P. minuta tadpoles is compared with that of other pseudids. Pseudis minuta larvae do not exhibit the ontogenetic coloration change reported for P. paradoxa. Considering larval coloration, larval size, and reports of adult size, acceleration or hypermorphosis are suggested as possible heterochronic mechanisms involved in the evolution of Pseudis.
A new species of rainfrog of the Eleutherodactylus diastema group from the Alta Talamanca Region of Costa Rica
Authors: Savage Jay M. 
Published: April 2008

AbstractA new species of Eleutherodactylus is described from southeastern Costa Rica. It is a member of the Eleutherodactylus diastema group characterized by a vivid pattern of dark spots on a yellow-orange ground color and features of digital disk morphology.
Differences in an ensemble of streamside salamanders (Plethodontidae) above and below a barrier to brook trout
Authors: Resetarits William J. 
Published: April 2008

AbstractI examined the species composition, relative abundances, and size distributions of an ensemble of streamside salamanders in two contiguous sections of an Appalachian headwater stream: one containing brook trout and one that was trout free. The two stream sections were separated by a natural waterfall that formed a permanent barrier to the upstream movement of fish. The two stream sections differed in the overall abundance of salamanders, the relative abundance of the six species present, and the size-distribution of the salamander ensemble. These results suggest that brook trout have an effect on the structure of co-occurring ensembles of salamanders, and that the continued coexistence of stream salamanders with brook trout does not indicate lack of strong ecological interactions.
Seasonal variation in nocturnal calling activity of a savanna anuran community in central Brazil
Authors: Moreira Glória , Barreto Larissa 
Published: April 2008

AbstractWe studied the calling activity of a savanna anuran assemblage and correlated two climatic parameters, rainfall and air temperature, with anuran calling. We made observations from September 1991 until March 1993 and quantified nocturnal calling activity by counting the number of calling males for each species present in a permanent pond. Bufo paracnemis had the shortest calling activity period and Physalaemus cuvieri had a seasonal calling period, lasting a maximum of four months. Diversity of calling males and species richness reached a peak in the first three months of the rainy season. Comparisons with other populations indicate that the reproductive period of P cuvieri varies along its geographical distribution in a manner related to regional climatic conditions.
Evolutionary and paleogeographical effects on the distribution of the Triturus cristatus superspecies in the central Balkans
Authors: Crnobrnja-Isailović J. , Dzukić G. , Krstić N. , Kalezić M.L. 
Published: April 2008

Abstract
A synthesis of all known data on the crested newt group assigns the Balkan peninsula as the center of origin or, at least, the area where the basic lineage of its species was limited in the late Miocene. According to the recent literature, the geological structure of the Balkan region changed considerably during the Tertiary. These geological processes could have had a considerable impact on crested newt divergence and on the recent distribution of species. Using the number of rib-bearing vertebrae (RBVN), recently suggested as a simple and powerful tool for distinguishing four taxa of the T cristatus superspecies, we analysed 36 population samples collected all over former Yugoslavia. The hypothesised recent distribution of the crested newt species, based on frequency distribution of RBVN, appears to correspond well to neotectonic events in the past.
The effect of inundation on hibernating Bufo bufo and Bufo calamita
Authors: Bosman W. , van Gelder J.J. , Strijbosch H. 
Published: April 2008

Abstract
Inundation effects on terrestrially hibernating Bufo bufo and B. calamita are reported. Mortality caused by experimental inundation of seminatural hibernation sites was high in B. calamita and very low in B. bufo. In a floodplain eight telemetrically monitored B. bufo withstood flooding during a period of 25-35 days without leaving their hibernation sites. After this period the emerging toads suffered mortality by floating down the river depending on the water level at the moment of emerging. The importance of floodsafe areas in floodplains is demonstrated.
Thermal ecology and reproductive cyclicity of the snake Natrix tessellata in south-eastern Austria and central Italy: a comparative study
Authors: Luiselli Luca , Zimmermann Petra 
Published: April 2008

Abstract
Aspects of thermal ecology and reproductive cyclicity are compared in two populations of the dice snake (Natrix tessellata), a semi-aquatic natricine species widely distributed across Europe. One population was studied near Leibnitz, Styria (south-eastern Austria), and the other one was studied in the Mounts of Tolfa near Rome (Latium, central Italy). The climate was strongly colder in the Austrian than in the Italian site. Snakes of both populations were similar in various traits, including average body temperature, higher mean body temperature of gravid than non-gravid individuals, significantly higher substratum temperatures selected by gravid than by non-gravid individuals, trends of relationships between body, air and substratum temperatures, average length of reproductive females, and average preparturition mass of reproductive females. However, Austrian snakes were found in water significantly less often than their Italian conspecifics (although in both populations nearly all individuals occurred close to water bodies), and showed a lower frequency of reproduction (biannual rather than annual) than Italian ones. The presented data are discussed in the light of suboptimal occupation of the colder area by Austrian snakes, and conservative rigidity of natural history and ecological traits of such a widespread species as N. tessellata.
The taxonomic status of the sea snake Hydrophis czeblukovi (Kharin, 1984) from north-west Australian waters
Authors: Rasmussen Arne Redsted , Smith Lawrence 
Published: April 2008

AbstractHydrophis czeblukovi, a species only known from north-west Australian waters, is redescribed using external and internal morphological characters and is compared with its congeners. Hydrophis geometricus Smith, 1986 is synonymized with H. czeblukovi.
Una especie nueva de Epipedobates (Amphibia, Anura, Dendrobatidae) de Perú
Authors: Morales Víctor R. , Velazco Paul M. 
Published: April 2008

Abstractn. Se describe una especie nueva de Epipedobates del grupo petersi de la ladera occidental de la cordillera Yanachaga-Chemillen, Departamento de Pasco, Perú, y se sugiere la inclusión de E. bilinguis y E. parvulus en el grupo petersi.
Visceral anatomy of the Malaysian snake genus Xenophidion, including a cladistic analysis and allocation to a new family (Serpentes: Xenophidiidae)
Authors: Wallach Van , Günther Rainer 
Published: April 2008

AbstractThe internal anatomy of Xenophidion is described and compared with that of members of other snake families. A suite of primitive characters eliminates Xenophidion as a possible member of the Caenophidia; only two characters could conceivably suggest a relationship to the Caenophidia and both are examples of losses and thus of low phylogenetic value in assessing relationships. However, among lower snakes a sister group relationship is demonstrated with the Tropidophiidae of the Neotropical region. Besides possessing nearly identical viscera and topographical arrangement thereof, Xenophidion shares several characters with the Tropidophiidae. A new family is created to contain the genus, the Xenophidiidae. The Xenophidiidae share one synapomorphy with both the Tropidophiidae and Bolyeriidae. Therefore, it is proposed that these three families be united in the superfamily Tropidophioidea. A phylogenetic analysis of 52 characters results in the following preferred hypothesis of relationships: (Boinae, (((Bolyeria, Casarea), (Xenophidion, ((Exiliboa, Ungaliophis), (Trachyboa, Tropidophis)))), Acrochordus)).
Estimating abundance and biomass of a Speleomantes strinatii (Caudata, Plethodontidae) population by temporary removal sampling
Authors: Salvidio Sebastiano 
Published: April 2008

AbstractA rock-face population of the European plethodontid Speleomantes strinatii (Aellen, 1958) was studied along a small Apennine stream, in northwest Italy. Three temporary removal samples were taken in October, from 1993 to 1996, to estimate population structure, abundance and biomass. Body-size polymodal frequency distributions were resolved into separate components (i.e., estimated age classes) using the log-differences method. Each year's sample was composed of two juvenile age classes plus a mixed component in which large immature individuals and sexually mature salamanders were present. The analysis of removal data showed that capture probabilities were homogeneous within each annual sampling and were similar between juveniles and adults (mean values being 0.33 and 0.26, respectively). The population density varied between 0.6 and 1.0 individuals/m2 of rock face (average 0.8) and biomass, expressed as wet weight, between 0.98 and 1.54 g/m2 (average 1.25 g/m2). Temporary removal sampling was effective in providing autoecological data on European plethodontid salamanders living in such relatively complex microhabitats as vertical rock faces. Moreover, the results suggest that temporary removal methods can be a useful tool in monitoring amphibian long-term population changes.