Large Frog Research Articles

Helminth communities of Leptodactylus latrans (Anura: Leptodactylidae) from the Atlantic rainforest, south-eastern Brazil.

The helminth fauna associated with Leptodactylus latrans, a large frog living in a disturbed environment of Atlantic rainforest in south-eastern Brazil, was evaluated. We found eight helminth taxa, including five nematode species, Falcaustra mascula, Oswaldocruzia subauricularis, Physaloptera sp., Rhabdias sp. and an unidentified cosmocercid, two trematodes, Gorgoderina parvicava and Haematoloechus fuelleborni, and one larval cestode. The overall prevalence of infection was 63.2% with a mean intensity of 11.3±3.8. The cosmocercid nematode and O. subauricularis showed the highest prevalences, although the trematode G. parvicava was the most abundant and dominant parasite species. Host size positively influenced both the intensity of infection and parasite species richness. Our data suggest that the juvenile individuals of L. latrans are more susceptible to parasitic infection than the adults. The comparison of the similarity of this community component with that found in other studies in South America shows that, as well as the characteristics of the host, the sampling area also influences the parasitic fauna. Therefore, the results of this study agree that the helminth communities of frogs have relatively low species richness and dominance of generalist species.

Frog Swarms: Earthquake Precursors or False Alarms?

Simple SummaryMedia reports linking unusual animal behaviour with earthquakes can potentially create false alarms and unnecessary anxiety among people that live in earthquake risk zones. Recently large frog swarms in China and elsewhere have been reported as earthquake precursors in the media. By examining international media reports of frog swarms since 1850 in comparison to earthquake data, it was concluded that frog swarms are naturally occurring dispersal behaviour of juveniles and are not associated with earthquakes. However, the media in seismic risk areas may be more likely to report frog swarms, and more likely to disseminate reports on frog swarms after earthquakes have occurred, leading to an apparent link between frog swarms and earthquakes.In short-term earthquake risk forecasting, the avoidance of false alarms is of utmost importance to preclude the possibility of unnecessary panic among populations in seismic hazard areas. Unusual animal behaviour prior to earthquakes has been reported for millennia but has rarely been scientifically documented. Recently large migrations or unusual behaviour of amphibians have been linked to large earthquakes, and media reports of large frog and toad migrations in areas of high seismic risk such as Greece and China have led to fears of a subsequent large earthquake. However, at certain times of year large migrations are part of the normal behavioural repertoire of amphibians. News reports of “frog swarms” from 1850 to the present day were examined for evidence that this behaviour is a precursor to large earthquakes. It was found that only two of 28 reported frog swarms preceded large earthquakes (Sichuan province, China in 2008 and 2010). All of the reported mass migrations of amphibians occurred in late spring, summer and autumn and appeared to relate to small juvenile anurans (frogs and toads). It was concluded that most reported “frog swarms” are actually normal behaviour, probably caused by juvenile animals migrating away from their breeding pond, after a fruitful reproductive season. As amphibian populations undergo large fluctuations in numbers from year to year, this phenomenon will not occur on a yearly basis but will depend on successful reproduction, which is related to numerous climatic and geophysical factors. Hence, most large swarms of amphibians, particularly those involving very small frogs and occurring in late spring or summer, are not unusual and should not be considered earthquake precursors. In addition, it is likely that reports of several mass migration of small toads prior to the Great Sichuan Earthquake in 2008 were not linked to the subsequent M = 7.9 event (some occurred at a great distance from the epicentre), and were probably co-incidence. Statistical analysis of the data indicated frog swarms are unlikely to be connected with earthquakes. Reports of unusual behaviour giving rise to earthquake fears should be interpreted with caution, and consultation with experts in the field of earthquake biology is advised.

Amphibian communities in natural and constructed ridge top wetlands with implications for wetland construction

Among the many causes linked to amphibian declines, habitat loss and alteration remain the most significant. Lack of federal protection for isolated wetlands has resulted in loss of amphibian breeding habitat without subsequent mitigation. Additionally, wetlands built for mitigation often do not replicate lost natural wetlands in structure or ecological processes. The long-term role of constructed wetlands for amphibian conservation is poorly understood because monitoring is often lacking. Our objective was to compare amphibian communities of natural wetlands to 2 types of constructed wetlands in the Daniel Boone National Forest, Kentucky. We measured habitat variables including canopy closure, hydrology, upland coarse woody debris, aquatic vegetation, maximum water depth, and Ohio Wetland Rapid Assessment Score at each wetland and quantified species-specific amphibian capture per unit effort using dip-netting. Wood frogs (Lithobates sylvaticus) and marbled salamanders (Ambystoma opacum) were almost exclusively found in natural, ephemeral wetlands, whereas large frogs (L. clamitans, L. catesbeianus, L. palustris) were primarily found breeding in permanent, constructed wetlands. Permutational analysis of variance indicated significant differences in amphibian communities between constructed and natural wetland types. Redundancy analysis indicated that hydrology and canopy closure best explained the differences in community composition between natural and constructed wetlands. Regression analyses and subsequent model ranking showed that greater captures per unit effort for eastern newts (Notopthalmus viridescens) and green frogs (L. clamitans) were predicted by increasing wetland size and depth, respectively, whereas mole salamanders (Ambystoma sp.) were negatively associated with the amount of aquatic vegetation and positively associated with wetland depth. As amphibian conservation and management become increasingly important in light of recent population declines and habitat loss, the ability to construct wetlands that provide amphibian habitat and to monitor how amphibians respond will be crucial to preservation of species diversity. Our research underscores the need for monitoring constructed wetlands to assess ecological condition. We provide suggestions to land managers who aim to construct isolated wetlands for amphibians. © 2013 The Wildlife Society.

168 A NONINVASIVE, TRANSDERMAL ABSORPTION APPROACH FOR EXOGENOUS HORMONE INDUCTION OF SPAWNING IN THE NORTHERN CRICKET FROG, ACRIS CREPITANS: A MODEL FOR SMALL ENDANGERED AMPHIBIANS

The World Conservation Union (IUCN) currently recognises Eleutherodactylus locustus from Puerto Rico and Plectrohyla acanthodes from Mexico and Guatemala as critically endangered, and they are recommended for ex situ breeding by several amphibian conservation organizations (e.g. AZA, ATAG, RCP, and AARK). Because of their very small and delicate bodies, conventional injectable methods developed for hormonally stimulating spawning in larger frogs and toads are undesirable, because this can result in trauma and injury. Recently, a protocol was developed for inducing spawning in frogs by co-injection of a gonadotropin-releasing hormone agonist (GnRHa) with metoclopramide-HCl (MET), a dopamine antagonist (Amphiplex; Trudeau et al. 2010 Rep. Biol. Endo. 8, 36). The goal of this study, therefore, was to determine the effectiveness of Amphiplex using 3 routes of exogenous treatments: (1) direct IP injection (0.4 µg of GnRHa + 10 µg of MET per gram of body weight), (2) injection into prey (1 µg of GnRHa + 25 µg of MET per insect) before feeding, and (3) a 60-min immersion in 10 mL of pond water containing 0.17 µg of GnRHa + 0.42 µg of MET per microliter. The northern cricket frog (Acris crepitans), a very common local species, was used as a model because it is also small, delicate, and difficult to handle. A total of 110 cricket frogs were caught locally either late or after their normal breeding season, sexed as males or females, and segregated into a control group that was housed similarly ex situ but not exposed to Amphiplex and the 3 Amphiplex experimental groups. The frogs were monitored daily for egg production and behavioural amplexus (potential spermiation). The results are summarised as follows (Table 1): of the frogs exposed to the Amphiplex-supplemented pond water, 84% of 38 females deposited eggs, and 6 pairs were observed in amplexus (indicating spermiation). Approximately 27% of more than 2242 eggs were found to develop cleavage divisions, and tadpoles were first observed in vitro after 4 days. In conclusion, to our knowledge this is the first report indicating that transdermal absorption of a reproductive hormone cocktail (e.g. Amphiplex) may serve in the application of assisted reproductive technology to increase the populations of critically endangered amphibians such as frogs and toads that may be too small or delicate for conventional methods of exogenous hormone treatments that require handling and injections. Table 1.Treated northern cricket frogs

Two remarkable prey items for a chicken:Leptodactylus fallaxMüller, 1926 predation upon the theraphosid spiderCyrtopholis femoralisPocock, 1903 and the colubrid snakeLiophis juliae(Cope, 1879)

Published records of amphibians preying on either large spiders or snakes in the wild are rare; this note documents predation by individuals of one amphibian species on both large spiders and snakes. Mountain chicken frogs (Leptodactylus fallax), which are amongst the largest frogs in the world, were observed successfully consuming the theraphosid spider Cyrtopholis femoralis on two occasions and attempting to consume another one on a further occasion on Montserrat. They were also found to have consumed the colubrid snake Liophis juliae on Dominica. This is the first theraphosid and the fourth snake species identified in the diet of L. fallax, and this frog is the first confirmed predator of C. femoralis.

Hickory Chickens

Hickory Chickens Sidney Saylor Farr (bio) Hickory chickens—that's what we called mountain morels. They were a delicacy, and they were a delight to find and eat. The morel mushrooms were sort of a pyramid shape and had indentations around the outside. Dad would hunt for them in early spring, when they were at their best, and most easily found. The family loved hickory chickens. I asked Dad why he called them that. He said, "Because they taste like chicken and grow near hickory trees." They were hard to find, but Dad seemed to know likely places to look for them. Following him, we walked uphill because it was easier to spot them around fallen logs and tree roots. It was a favorite activity to hunt for these morels. It was usual to run into other people also searching, but always in a friendly situation. In our part of the hills in southeastern Kentucky, we would all keep to our own chosen places to search. Dad loved hunting for them and would go into the woods and return with a saddlebag full of the morels. Mother would clean and slice them, roll them in flour, and then fry them. When they were served with the meal they tasted almost like chicken. As so often with any normal chore, both my parents worked this process, with Dad bringing in the morels and Mama preparing them. One time Dad brought home a large frog he had caught, and it was Mama's job to prepare it. She thought the frog was dead, but when she started to cut into it, the frog jerked. It was such a shock that she fainted! I always enjoyed those times in the woods, whether hunting for hickory chickens or playing games. In the mountains there are certain places that feel different. There was a cove where I used to love to go because it made me feel so good. Once I stepped over a certain point, a good feeling would come over me. When I stepped into that area, there was a special energy that surrounded me, and I could feel it as long as I stayed within that certain area. I would usually go there with my mother, Aunt Betty, and Aunt Laura. Aunt Laura was four years older than me, and she had a very inventive imagination. We picked out a certain tree that was the "doctor," and another tree was the "nurse," and the small bushes were the "children." Aunt Laura usually claimed the prettiest trees as hers, and I had to take those that were left. We played many games of make-believe among those trees. [End Page 91] I loved listening to Aunt Betty talk. She had a talent for tying things together. She would tell about something that happened, and then she would tell the history. "That was the year everybody got the flu," or "that was the year it flooded in the spring." That always made family history seem clear to me. Aunt Laura had such an imagination; you never knew if she was lying about something or if it was make-believe. I don't know if there's a difference between lying and make-believe, but mother was always sure that if you talked about something that didn't happen, it was a lie. I was always writing something and hiding the papers in the loft; they were thoughts, fantasies, daydreams, and so forth. Mama found them one day and because of her upbringing was horrified at all the lies I told; I hadn't written anything about being Christian or about Bible topics. She spoke to Dad and told him they needed to do something about this. Dad never mentioned it to me. I was distressed that she thought it was all lies, and I felt guilty for continuing to write, but I worked it out. I made a bargain with God. I promised that if he wouldn't make it a sin for me to write and read other books, I would read the Bible every day. And I did. I read completely through several times. And I kept on writing. [End Page 92...

Not just small, wet, and cold: effects of body size and skin resistance on thermoregulation and arboreality of frogs

We used simulations from a biophysical model that integrates interlinked exchanges of energy and water between frogs and their environments to address questions about the limits to thermoregulation and about adaptations for arboreality. Body size and cutaneous resistance (Rc) both significantly affected body temperature (Tb) and the time to desiccate to 70% of standard mass (an ecologically relevant metric of desiccation). Cutaneous resistances < 25 s/cm allow basking frogs to elevate their Tb several degrees above ambient, but Rc above 25 had little additional effect on Tb. Small frogs (<10 g) are able to elevate their Tb above ambient while basking, even with small Rc. Large frogs must have greater skin resistances to be able to elevate body temperatures above ambient, yet large frogs take longer to desiccate to 70% of their standard mass. Frogs can avoid rapid desiccation with high Rc, a large body size, or some combination of these traits. Our literature survey indicates that frogs with a combination of Rc and body size that would result in long times to desiccate to 70% of standard mass tend to be arboreal, suggesting that those species may be selectively favored in a niche that often requires frogs to be away from water sources for extended periods of time.

The Harvest of Endemic Amphibians for Food in Eastern Madagascar

Deliveries of edible, endemic amphibians to a restaurant in eastern Madagascar were monitored over a five-month period in the 2008 austral summer. Each frog collector was interviewed on arrival and information was obtained on collection locality, methods, frequency, as well as recording the number of frogs delivered. A total of 3,233 frogs were delivered to the restaurant during the study, averaging 249 per week. All of the 21 interviews concerned frogs collected in forest habitats at night by teams of between one and three people. Collection occurred in four localities, one of which (Fierenana) necessitated public transport to deliver the frogs. Effort at Fierenana was typically higher than at other sites with collectors frequently spending at least one night in the forest and traveling around 8.3 hours between their homes and forest collection locations. Income generated went directly to the collectors, who always delivered the frogs in person, and supply was determined by their available time, frog abundance, and weather conditions. Although the restaurant had no stated minimum quantity for purchase, small frogs were refused and collectors aimed for a minimum of 60 large frogs per delivery. The income generated by local amphibian collectors at Fierenena was similar for non-threatened edible species destined for domestic consumption (0.29 US$) and the Critically Endangered Mantella milotympanum collected for overseas export (0.32 US$). The harvest of edible frogs provides important income for individual hunters but additional study is needed to investigate its impact on frog populations and to develop methods to link sustainable collection practices with forest management.

Demography and Movement in a Relocated Population of Oregon Spotted Frogs (Rana pretiosa): Influence of Season and Gender

We used five years of recapture data and Bayesian estimation to assess seasonal survival, movement, and growth of Oregon Spotted Frogs (Rana pretiosa) relocated into created ponds at Dilman Meadow in Oregon, USA. We evaluate hypotheses specific to the relocation and elucidate aspects of R. pretiosa life history that are poorly known. The odds of survival of relocated individuals during the first year following relocation were 0.36 times the survival odds of relocated and non-relocated frogs after one year since the relocation. Survival rate was higher for large frogs. After accounting for frog size, we found little variation in survival between ponds at Dilman Meadow. Survival was lowest for males during the breeding/post-breeding redistribution period, suggesting a high cost of breeding for males. The highest survival rates occurred during winter for both genders, and one small spring was used heavily during winter but was used rarely during the rest of the year. Individual growth was higher in ponds that were not used for breeding, and increased with increasing pond age. Our study supports other evidence that R. pretiosa use different habitats seasonally and are specific in their overwintering habitat requirements. Because frogs were concentrated during winter, predator-free overwintering springs are likely to be of particular value for R. pretiosa populations.

Latitudinal Variation in the Prevalence and Intensity of Chytrid (Batrachochytrium dendrobatidis) Infection in Eastern Australia

Chytridiomycosis is a recently emerged, infectious skin disease of amphibians that has been linked directly to mass mortalities, population declines, and species extinctions worldwide. An understanding of the factors that limit the distribution and abundance of Batrachochytrium dendrobatidis (the etiological agent of chytridiomycosis) is urgently required. We conducted disease surveys at 31 lowland sites distributed north-south along 2315 km of the Australian east coast that encompassed 20.8 degrees of latitude. A total of 863 adult male stony creek frogs (Litoria lesueuri complex) were sampled, and the overall prevalence of B. dendrobatidis infection was 26%. B. dendrobatidis was detected at 77% of the sites, including sites at the northern and southern limits of the latitudinal transect. Frogs from temperate regions, however, had significantly more intense infections than did their tropical counterparts, often carrying an order of magnitude more B. dendrobatidis zoospores, suggesting that at low elevations, temperate frogs are at higher risk of chytridiomycosis-induced mortality than are tropical frogs. The prevalence and intensity of B. dendrobatidis infections were significantly greater at sites with high rainfall (>33 mm in the 30 days prior to sampling) and cool temperatures (stream temperature 1 h after sunset < 23 degrees C). Although climatic variables explained much of the variation in the prevalence and intensity of B. dendrobatidis infections between infected and uninfected sites, frog snout-vent length was consistently the best predictor of infection levels across infected sites. Small frogs were more likely to be infected and carried more intense infections than larger frogs, suggesting either that frogs can outgrow their chytrid infections or that the disease induces developmental stress that limits growth. Our results will directly assist amphibian disease researchers and wildlife managers, whose conservation efforts should focus on those amphibian populations living within the B. dendrobatidis climatic envelope that we have described.

Macroecology and extinction risk correlates of frogs

ABSTRACTAim Our aim was to test whether extinction risk of frog species could be predicted from their body size, fecundity or geographical range size. Because small geographical range size is a correlate of extinction risk in many taxa, we also tested hypotheses about correlates of range size in frogs.Location Global.Methods Using a large comparative data set (n = 527 species) compiled from the literature, we performed bivariate and multiple regressions through the origin of independent contrasts to test proposed macroecological patterns and correlates of extinction risk in frogs. We also created minimum adequate models to predict snout–vent length, clutch size, geographical range size and IUCN Red List status in frogs. Parallel non‐phylogenetic analyses were also conducted. We verified the results of the phylogenetic analyses using gridded data accounting for spatial autocorrelation.Results The most threatened frog species tend to have small geographical ranges, although the relationship between range and extinction risk is not linear. In addition, tropical frogs with small clutches have the smallest ranges. Clutch size was strongly positively correlated with geographical range size (r2 = 0.22) and body size (r2 = 0.28).Main conclusions Our results suggest that body size and fecundity only affect extinction risk indirectly through their effect on geographical range size. Thus, although large frogs with small clutches tend to be endangered, there is no comparative evidence that this relationship is direct. If correct, this inference has consequences for conservation strategy: it would be inefficient to allocate conservation resources on the basis of low fecundity or large body size; instead it would be better to protect areas that contain many frog species with small geographical ranges.

Species boundaries among barred river frogs, Mixophyes (Anura: Myobatrachidae) in north-eastern Australia, with descriptions of two new species

Mixophyes are large ground-dwelling myobatrachid frogs from eastern Australia and New Guinea. We use analyses of allozyme frequencies, nucleotide sequences of mitochondrial DNA and morphology to define species boundaries in Mixophyes from the Wet Tropics World Heritage Area of northern Queensland. The molecular analyses identify a minimum of three species in the region. Morphometric and meristic analyses corroborate these distinctions. The existence of two of these species was not previously suspected, and they are formally described herein.

Factors affecting escape behavior of Iberian green frogs (Rana perezi)

Theoretical models and empirical evidence suggest that prey should not flee immediately upon detecting an approaching predator, but instead should adjust their escape response to minimize the costs of flight. Similarly, after deciding to escape, animals should tend to adjust the magnitude and characteristics of their escape response according to the perceived level of predation risk. Although these hypotheses have been tested in some prey types, it remains for their applicability to a wider range of taxa to be ascertained and for a larger variety of microhabitat and environmental conditions to be considered. We simulated predator approaches to Iberian green frogs (Rana perezi Seoane, 1885) in the field. Frogs were approached while they were foraging alone at the edge of water, and they escaped by jumping into the water. Results showed that escape decisions of frogs are influenced by microhabitat variables and body size. Both the approach distance allowed to the predator and the distance jumped by the frogs in response to the approach were positively correlated with the initial distance of the frog from the water's edge; they were also dependent on vegetation cover at the edge of and in the water. Small frogs appeared to rely on crypsis more than large frogs and allowed shorter predator approach distances. They also remained still on the water surface after jumping more often than large frogs. We conclude that such flexibility in the escape response may allow frogs to reduce predation risk without incurring excessive costs.

Two hundred and ten years looking for the Giant Burrowing Frog

The giant burrowing frog Heleioporus australiacus (Shaw) is a large, morphologically distinctive, but cryptic frog found in south eastern Australia. This paper reviews the literature pertaining to the Giant Burrowing Frog. It is a forest dependent species found on the coast and adjacent ranges of south-eastern Australia, with five congeners in south-west Western Australia. The species is listed as vulnerable in NSW and Victoria and under Commonwealth legislation, although there is no obvious cause for a decline nor is it clear how much decline has occurred. Proposed threats to the species survival include forestry operations, habitat destruction, introduced species, pollutants, increased UV and disease. A large gap exists in the species distributional records and H. australiacus may represent two distinct species, although the evidence for this remains inconclusive. Standard detection methods for frogs do not apply well to the Giant Burrowing Frog and alternative methods are required to provide a more det...

Feeding habits of the frog Pleurodema diplolistris (Anura, Leptodactylidae) in Quaternary sand dunes of the Middle Rio São Francisco, Bahia, Brazil

In this work, we investigate the feeding habits of Pleurodema diplolistris, the most abundant anuran species of the São Francisco sand dunes, during a period of slightly over one year. The fieldwork was undertaken during four excursions to a sand dune in the semiarid Caatinga, Brazil, and the analyses were based on stomach contents. Pleurodema diplolistris were not active during the dry season. The important food categories in diet were Isoptera (winged forms), Coleoptera, and Formicidae. Small and large animals had different food consumption patterns: small frogs showed positive electivity for termites and large frogs, for ants. This pattern was strongly influenced by large male food electivity. High levels of termites consumption occurred during the days of greater capture success. The pattern of high consumption of termites detected here is different from that described in another study on lizards from the same locality and sampled in the same periods. We discuss alternative hypotheses that could explain the observed patterns.

A combined confocal and magnetic resonance microscope for biological studies

Complementary data acquired with different microscopy techniques provide a basis for establishing a more comprehensive understanding of cell function in health and disease, particularly when results acquired with different methodologies can be correlated in time and space. In this article, a novel microscope is described for studying live cells simultaneously with both confocal scanning laser fluorescence optical microscopy and magnetic resonance microscopy. The various design considerations necessary for integrating these two complementary techniques are discussed, the layout and specifications of the instrument are given, and examples of confocal and magnetic resonance images of large frog cells and model tumor spheroids obtained with the compound microscope are presented.

Ontogenetic change in the diet of the pond frog, Rana nigromaculata

I analyzed 478 diet samples of Rana nigromaculata across its natural size range to examine the dietary changes of this species during postmetamorphic ontogeny. As the frogs increased in size, they increased total diet volume, but decreased the number of prey items. Also, individuals ontogenetically increased the mean, minimum and maximum prey volume in the stomach. The mean volume of the major prey taxa consumed by the frogs varied considerably. Small prey, such as ants and dipterans, were found less frequently as the size of the frogs increased, but large prey, such as beetles and orthopterans, were more frequently recovered from larger frogs. These results suggest that ontogenetic diet change should be considered when the structure of an anuran community is investigated using food niche analysis.

Commentary: Treatments for Enuresis: Criteria, Mechanisms, and Health Care Policy

We are fortunate to have the case of treatments for enuresis to teach a historical lesson about the pitfalls of our current enthusiasm for empirically supported treatments. The treatment of enuresis has a long and very colorful history dating as far back as 1550 B.C. Glicklich (1951) recounted two instructive examples of “treatments.” In West Africa, children who wet the bed were “treated” by attaching a large frog to their waist, and this apparently frightened them into being dry. Among the Navaho tribe, one preferred treatment was a ritual that required enuretic children to stand naked over a burning bird’s nest, and this was believed to produce a cure of bedwetting because birds did not soil their nests. We may snicker at these practices of the past, but the laugh is really on us. These practices worked, and they worked on a variable interval schedule of reinforcement because they were occasionally followed by the spontaneous cessation of bedwetting, something that happens for about 16 out of every 100 children within a 12-month period. It is no wonder then that so many peculiar treatments have been tried, and so many odd practices have persisted. In some ways what we really need to know about treatments for bedwetting is which treatments definitely do not work. Such a Popperian approach to the issue of identifying empirically supported treatments is counterJournal of Pediatric Psychology, Vol. 25, No. 4, 2000, pp. 219–224

Inoculative freezing by environmental ice nuclei in the freeze-tolerant wood frog, Rana sylvatica.

Efficacy of inoculative freezing by ice nuclei in a simulated winter environment was studied in the wood frog (Rana sylvatica), a freeze-tolerant species that overwinters on the forest floor beneath organic detritus. Adult frogs were confined to plastic canisters and cooled to -2 degrees C over 24 hr with their ventral skin in contact with substrate (humic soil hydrated to 40, 10, or 5%, or soil/peat mixture hydrated to 20 or 10%, w/w), or their dorsal skin in contact with damp leaf mould. Whereas only 20% of control frogs cooled in dry, plastic canisters froze, freezing occurred in nearly all (98%) frogs contacting soil or leaf mould. Inoculation was briefly delayed in frogs exposed to drier substrates. Frogs exposed to an unfreezable substrate (humic soil, 5% moisture) themselves froze, apparently due to the action of constituent nuclei which commonly occur in natural materials. Although the surface over which inoculation can occur is greater in larger frogs, inoculation susceptibility was not correlated with body mass in our frogs (mean +/- SE body mass = 14.0 +/- 0.2 g; range, 9.8-17.8 g). We conclude that the high susceptibility to inoculative freezing in R. sylvatica, which is conferred by its moist, highly permeable integument, promotes freeze tolerance by ensuring that inoculation commences at relatively high temperatures.

The taxonomic identity of a population of terrestrial Leiopelma (Anura: Leiopelmatidae) recently discovered in the northern king country, New Zealand

A terrestrial endemic frog resembling Leiopelma archeyi was discovered in the Whareorino Forest, northern King Country, New Zealand, in 1991, where it is broadly sympatric with L. hochstetteri. To clarify its taxonomic status, allozyme electrophoresis of toe tissue was used to compare it genetically with four other populations of terrestrial Leiopelma (L. archeyi from Tapu and Tokatea, Coromandel; L. hamiltoni from Stephens Island; L. pakeka from Maud Island). Thirteen presumed genetic (allozyme) loci could be consistently scored for the five populations. At 11 loci, no genetic differences were found between the Whareorino frog and the two Coromandel L. archeyi populations. Allelic frequencies differed slightly at two loci. We therefore conclude that the terrestrial Whareorino frog represents a western population of L. archeyi. L. hamiltoni from Stephens Island is genetically closer to L. archeyi than is L. pakeka from Maud Island. The Whareorino L. archeyi population is morphologically similar to Coromandel L. archeyi populations, although multivariate analysis suggests subtle morphological differences, including the relative position of the nostril. Size comparisons between Whareorino and three Coromandel sites (Moehau, Tapu, Tokatea) show there were more larger frogs (35–38 mm snout‐vent length) at Whareorino and Tokatea compared with Moehau and Tapu, where maximum snout‐vent lengths were 34 and 36 mm, respectively.