Phylogenetic relationships among marsupial frog genera (Anura: Hylidae: Hemiphractinae) based on evidence from morphology and natural history

We reassess the phylogenetic relationships of genera of hemiphractine hylid frogs (Marsupial Treefrogs) and discuss the evolution of several distinctive characters within this group using parsimony analysis. Fifty-one morphological and life-history characters were sampled from two species of Cryptobatrachus , three species of Flectonotus , 17 species of Gastrotheca , all five species of Hemiphractus , and one species of Stefania as the ingroup and three hyline, one phyllomedusine, and one pelodryadine species as outgroups. Our results support the mon-ophyly of Flectonotus, Cryptobatrachus , and Hemiphractus. Gastrotheca is paraphyletic with respect to Hemiphractus , dorsal pouches were lost in the ancestor of Hemiphractus. Direct development is a synapomorphy for Hemiphractinae and tadpoles were regained independently several times. These results stand in stark contrast to the prevailing paradigm regarding marsupial frog relationships.     

中国43种蛙类鸣声特征数据集

无尾两栖动物的鸣声通常具有物种特异性,了解其鸣声特征信息,是利用生物声学进行物种多样性调查及物种监测的前提。本文汇总、整理了2012–2020年间利用高保真录音设备在野外记录的43种(隶属于7科26属)无尾两栖动物的鸣声数据,以及相应的鸣声采集信息。对音频文件进行降噪处理后,提供了由61个鸣声的波形图及语图组成的鸣声特征数据集。本数据集展示了鸣声的多种时域和频域信息,如单音节或多音节、音节数、音节时长、音节间隔、鸣声时长、主频、基频、谐波等,为我国无尾两栖类的声学研究、物种多样性调查及鸣声监测提供了数据支持。     

Muscle development in the abdominal region of Larval Hylidae (Amphibia: Anura)

Larval muscle development in the abdominal region of five species of hylid frogs (Scinax nasicum, S. fuscovarium, Hyla andina, Phyllomedusa boliviana, Gastrotheca gracilis) was studied using differential staining techniques. These five species represent three major hylid subfamilies. The development of the main abdominal muscles, the rectus abdominis, the two lateral muscles (obliquus externus and transversus), and the lateral pectoralis abdominalis is described. The number of myotomes of the rectus abdominis varies between five and six, and the abdominal muscles associated with the rectus abdominis (obliquus externus, pectoralis abdominalis, and rectus cervicis) vary interspecifically in time of appearance and configuration. The presence of gaps in the configuration of the rectus abdominis has been related to the lotic habits of the larvae. However, our observations indicate the presence of such gaps in larvae that inhabit lentic environments as well. These results suggest that the presence of these gaps is unrelated to larval habitat. There are relatively small differences in muscle morphology among these closely related species, which apparently cannot be explained by morphological adaptations related to their ecology. In the species studied, the number of elements that form the abdominal musculature in larvae is equal to that observed in adults. Likewise, the general morphology of the muscles is ontogenetically conserved. This suggests that both the axial skeleton and musculature are more ontogenetically conserved in relation to the substantial changes that are observed in the skull and head muscles of developing anurans. J. Morphol. 241:275–282, 1999. © 1999 Wiley‐Liss, Inc.     

Carnivory and resource-based niche differentiation in anuran larvae: implications for food web and experimental ecology

1.  Food webs represent the paths of material and energy flow through organisms in an ecosystem. Anuran larvae are important components of pond food webs: they are abundant, consume large quantities of food and serve as prey for many organisms. However, there are very basic uncertainties about the feeding ecology of anuran larvae; for instance, as to which trophic level they belong and whether species differ in resource use. Because anuran larvae have been employed in model systems in experimental ecology for decades, these uncertainties could lead to misinterpretation of published experiments, or inadequate designs of experiments directed at general, conceptual issues in ecology.
2.  Using ¹³C and ¹⁵N stable isotope and gut content analyses of free-ranging and enclosed tadpoles of four ranid species ( Lithobates sylvaticus , L. pipiens , L. clamitans , L. catesbeianus ) in the food webs of six wetlands, we tested the following null hypotheses: (i) that anuran larvae are strict primary consumers; (ii) that they are non-selective feeders and therefore exhibit little feeding niche differentiation; (iii) that they are opportunistic consumers and (iv) that their diet remains unchanged through ontogeny.
3.  All four species consumed and assimilated substantial amounts of animal food; bullfrog larvae, in particular, appear to be predatory. Significant feeding niche differentiation among species occurred with respect to the sources of carbon, consumption of animal matter and nutritional quality of food ingested. We further documented opportunistic feeding habits and ontogenetic shifts in diet.
4.  Collectively, these studies revealed complex trophic relationships that might require a reconsideration of the role of anuran larvae in pond food webs, as well as a reinterpretation of results of previous studies employing anuran larvae in model experimental systems.     

Medusins: A new class of antimicrobial peptides from the skin secretions of phyllomedusine frogs

Natural drug discovery represents an area of research with vast potential. The investigation into the use of naturally-occurring peptides as potential therapeutic agents provides a new “chemical space” for the procurement of drug leads. Intensive and systematic studies on the broad-spectrum antimicrobial peptides found in amphibian skin secretions are of particular interest in the quest for new antibiotics to treat multiple drug-resistant bacterial infections. Here we report the molecular cloning of the biosynthetic precursor-encoding cDNAs and respective mature peptides representing a novel group of antimicrobial peptides from the skin secretions of representative species of phyllomedusine leaf frogs: the Central American red-eyed leaf frog (Agalychnis callidryas), the South American orange-legged leaf frog (Phyllomedusa hypochondrialis) and the Giant Mexican leaf frog (Pachymedusa dacnicolor). Each novel peptide possessed the highly-conserved sequence, LGMIPL/VAISAISA/SLSKLamide, and each exhibited activity against the Gram-positive bacterium, Staphylococcus aureus and the yeast, Candida albicans, but all were devoid of haemolytic effects at concentrations up to and including the MICs for both organisms. The novel peptide group was named medusins, derived from the name of the hylid frog sub-family, Phyllomedusinae, to which all species investigated belong. These data clearly demonstrate that comparative studies of the skin secretions of phyllomedusine frogs can continue to produce novel peptides that have the potential to be leads in the development of new and effective antimicrobials.     

Integumentary structure and its relationship to wiping behaviour in the common Indian tree frog, Polypedates maculatus

Skin of the Indian tree frog, Polypedates maculatus (Rhacophoridae), was studied in the context of self-wiping behaviour which functions to expel and distribute cutaneous secretions recently shown to retard evaporative water loss. The secretions contain both mucus and lipids and are derived from a common gland considered to be homologous with characteristic anuran mucous glands. The glands are bipotent and secrete both mucus and lipoid products which are evidently mixed within the glandular lumen. Another type of gland resembling characteristic anuran serous (or granular) glands is found in dorsal but not ventral skin, whereas the lipid-secreting mucous glands are found in skin associated with all body surfaces. There is no distinct, lipid-secreting gland present in the skin of this species other than the mucous glands. These histochemical data complement the earlier finding that resistance to evaporative water loss in this species is relatively small compared with phyllomedusine 'waterproof frogs which also exhibit wiping behaviour associated with secretion of lipids. Thus, wiping behaviour may have evolved in association with mucous secretions before dominant lipoid secretions resulted from strong selection for water conservation.     

Pattern and rate of ovary differentiation with reference to somatic development in anuran amphibians

The rate of somatic development of anuran amphibians is only roughly correlated with the rate of gonad differentiation and varies among species. The somatic stage of a tadpole often does not reflect its age, which seems to be crucial for gonad differentiation rate. We compared the morphology and differentiation of developing ovaries at the light and electron microscopy level, with reference to somatic growth and age of a female. Our observations were performed on 12 species of six families (Rana lessonae, R. ridibunda, R. temporaria, R. arvalis, R. pipiens, R. catesbeiana, Bombina bombina, Hyla arborea, Bufo bufo. B. viridis, Xenopus laevis, Pelobates fuscus) and compared with the results obtained by other authors. This allowed us to describe the unified pattern of anuran female gonad differentiation. Ovary differentiation was divided into 10 stages: I-III, undifferentiated gonad; IV, sexual differentiation; V, first nests of meiocytes; VI, first diplotene oocytes; VII-IX, increasing number of diplotene oocytes and decreasing number of oogonia and nests; X, fully developed ovary composed of diplotene oocytes with rudimental patches of oogonia. We distinguished three types of ovary differentiation rate: basic (most species), retarded (genus Bufo), and accelerated (green frogs of the subgenus Pelophylax genus Rana).     

Phylogenetic Relationships among Bufonoid Frogs (Anura: Neobatrachia) Inferred from Mitochondrial DNA Sequences

Nucleotide sequences of portions of the mitochondrial 12S and 16S ribosomal RNA genes were used to extend a recent study of anuran phylogeny (Hayet al., Mol. Biol. Evol.12: 928–937, 1995) and to further evaluate phylogenetic relationships within the Neobatrachia. An analysis of almost 900 nucleotides from each of 8 new representatives of the Dendrobatidae, Hylidae, Leptodactylidae, and Myobatrachidae, plus 14 available members of the Neobatrachia provides support for 2 major lineages (Bufonoidea and Ranoidea) within this anuran suborder. The neotropical Bufonoidea and their derivatives are monophyletic. There is an interesting association of the 2 Australian myobatrachids with the South African Heleophrynidae, and the Sooglossidae is one of the basal bufonoid lineages. Within the New World bufonoid frogs, a monophyletic Dendrobatidae is strongly supported. An Australian hylid (Pelodryadinae) shows close affinity with the South American hylid Phyllomedusinae. A group composed of Hylinae (HylaandSmilisca), Centrolenidae, Bufonidae, and the hylid Hemiphractinae, with the latter two clustered, was supported significantly. The addition of new taxa has more clearly defined some relationships within the suborder Neobatrachia and has indicated that the families Hylidae, Leptodactylidae, and Myobatrachidae may not be monophyletic.     

Phylogeny, Life History, and Ecology Contribute to Differences in Amphibian Susceptibility to Ranaviruses

Research that identifies the potential host range of generalist pathogens as well as variation in host susceptibility is critical for understanding and predicting the dynamics of infectious diseases within ecological communities. Ranaviruses have been linked to amphibian die-off events worldwide with the greatest number of reported mortality events occurring in the United States. While reports of ranavirus-associated mortality events continue to accumulate, few data exist comparing the relative susceptibility of different species. Using a series of laboratory exposure experiments and comparative phylogenetics, we compared the susceptibilities of 19 amphibian species from two salamander families and five anurans families for two ranavirus isolates: frog virus 3 (FV3) and an FV3-like isolate from an American bullfrog culture facility. We discovered that ranaviruses were capable of infecting 17 of the 19 larval amphibian species tested with mortality ranging from 0 to 100%. Phylogenetic comparative methods demonstrated that species within the anuran family Ranidae were generally more susceptible to ranavirus infection compared to species from the other five families. We also found that susceptibility to infection was associated with species that breed in semi-permanent ponds, develop rapidly as larvae, and have limited range sizes. Collectively, these results suggest that phylogeny, life history characteristics, and habitat associations of amphibians have the potential to impact susceptibility to ranaviruses.     

Osteological postcranial traits in hylid anurans indicate a morphological continuum between swimming and jumping locomotor modes

Anurans exhibit a particularly wide range of locomotor modes that result in wide variations in their skeletal structure. This article investigates the possible correlation between morphological aspects of the hylid postcranial skeleton and their different locomotor modes and habitat use. To do so, we analyzed 18 morphometric postcranial variables in 19 different anuran species representative of a variety of locomotor modes (jumper, hopper, walker, and swimmer) and habitat uses (arboreal, bush, terrestrial, and aquatic). Our results show that the evolution of the postcranial hylid skeleton cannot be explained by one single model, as for example, the girdles suggest modular evolution while the vertebral column suggests other evolutionary modules. In conjunction with data from several other studies, we were able to show a relationship between hylid morphology and habitat use; offering further evidence that the jumper/swimmer and walker/hopper locomotor modes exhibit quite similar morphological architecture. This allowed us to infer that new locomotor modalities are, in fact, generated along a morphological continuum. J. Morphol. 278:403–417, 2017. © 2017 Wiley Periodicals, Inc.     

Cladistic analysis and osteological descriptions of the frog species in the Leptodactylus fuscus species group (Anura, Leptodactylidae)

The genus Leptodactylus is predominantly Neotropical (a few species have colonized the southern Neartic region) and is distributed from Texas to Argentina and on certain Caribbean islands. Leptodactylus was divided into five groups of species: Leptodactylus melanonotus , Leptodactylus ocellatus, Leptodactylus fuscus , Leptodactylus pentadactylus and Leptodactylus marmoratus . Among these, the L. fuscus group is the one with most species, with 27 taxa. Characters unverified in most of the species are used to define the L. fuscus group. However, the monophyly of the group has never been tested rigorously in a quantitative phylogenetic context. Thus, the main goal of this study was to test such monophyly and to construct a phylogeny of the L. fuscus group. A matrix of 114 characters scored across 43 taxa was constructed, with 31 characters taken from external morphology, 58 from adult skeletons, 16 from larval chondrocranium, 5 from ethology and 4 from morphometric data were included. Out of all the species examined, 23 belonged to the ingroup and 20 to the outgroup. The data set was analysed with implied weights, by using TNT software. The monophyly of the group was strongly supported in the fittest cladogram obtained. The optimizations of some characters on this hypothesis support traditional evolutionary hypotheses. The optimizations also suggest the presence of paedomorphic character states in some species, which is also discussed.     

Oviposition by Danaus plexippus in relation to cardenolide content of three Asclepias species in the southeastern U.S.A.

Abstract. 1. Female monarchs were observed in the field ovipositing on a native North American milkweek host, Asclepias humistrata L. As in a comparable Australian study on an introduced novel host ( Asclepias fruticosa L.) we found post-alighting rejection of plants with low and high cardiac glycoside concentration (CG).
2. Most oviposition took place on plants with CG in the range 200–500 μg/0.1 g dry weight. Thin-layer chromatography showed no obvious qualitative difference in cardenolide types between accepted and rejected plants, excepting an indication that rejected plants may have a higher level of more polar cardenolides.
3. In a controlled laboratory experiment comparing oviposition on a low ( A.incarnata L.) vs high ( A.curassavica L.) CG host plant species we found no relationship between CG and oviposition on the low CG species, but a negative relationship in the high CG species. This corroborates our findings on oviposition on single host species in the field.
4. We also record the first indication of a physiological cost of monarch larvae feeding on plants high in CG. There was a significant negative relationship between survival of first instar larvae and CG levels in plants. This study opens the way for further work on the association of monarch butterflies and their toxic milkweed hosts.     

Phylogenetic analyses of mtDNA sequences reveal three cryptic lineages in the widespread neotropical frog Leptodactylus fuscus (Schneider, 1799) (Anura, Leptodactylidae)

Leptodactylus fuscus is a neotropical frog ranging from Panamá to Argentina, to the east of the Andes mountains, and also inhabiting Margarita, Trinidad, and the Tobago islands. We performed phylogenetic analyses of 12S rRNA, 16S rRNA, tRNA-Leu, and ND1 mitochondrial (mt) DNA sequences from specimens collected across the geographic distribution of L. fuscus to examine two alternative hypotheses: (i) L. fuscus is a single, widely distributed species, or (ii) L. fuscus is a species complex. We tested statistically for geographic association and partitioning of genetic variation among mtDNA clades. The mtDNA data supported the hypothesis of several cryptic species within L. fuscus. Unlinked mtDNA and nuclear markers supported independently the distinctness of a 'northern' phylogenetic unit. In addition, the mtDNA data divided the southern populations into two clades that showed no sister relationship to each other, consistent with high differentiation and lack of gene flow among southern populations as suggested by allozyme data. Concordance between mtDNA and allozyme patterns suggests that cryptic speciation has occurred in L. fuscus without morphological or call differentiation. This study illustrates a case in which lineage splitting during the speciation process took place without divergence in reproductive isolation mechanisms (e.g. advertisement call in frogs), contrary to expectations predicted using a biological species framework.  © 2006 The Linnean Society of London, Biological Journal of the Linnean Society, 2006, 87 , 325–341. No claim to original US government works.     

Direct and indirect effects of the introduced toad Bufo marinus (Anura: Bufonidae) on populations of native anuran larvae in Australia

Introduced species are frequently believed to have adverse effects on native biota and ecosystems. However, much of our knowledge of the ecological impacts of introduced species is anecdotal, and the mechanisms controlling these effects are often poorly understood. I used replicated artificial pond experiments to investigate the impact of eggs and hatchlings of the introduced toad Bufo marinus on populations of native anuran larvae (Limnodynastes ornatus and Litoria rubella) in Australia. Bufo marinus eggs and hatchlings are highly toxic to predatory native tadpoles. Under naturalistic conditions, populations of predatory L. ornatus tadpoles experienced significantly reduced survival when exposed to Bufo eggs and hatchlings. The impact of Bufo on L. ornatus survival was positively correlated with Bufo density. However, the toxic effects of Bufo on L. ornatus indirectly facilitated the survival of later-breeding L. rubella by altering predator-prey interactions between L. ornatus and L. rubella. Limnodynastes ornatus tadpoles are voracious predators of L. rubella eggs and hatchlings. Consequently, the negative impact of Bufo on populations of L. ornatus tadpoles reduced the intensity of predation by L. ornatus tadpoles on L. rubella eggs and hatchlings, thereby increasing L. rubella survival. The results demonstrate that B. marinus plays an important role in structuring native larval anuran communities via direct and indirect mechanisms, and that Bufo may have both negative and positive effects on populations of native anuran larvae. As far as I am aware, these are the first quantitative data to demonstrate that introduced fauna may affect populations of native biota via toxic effects.     

An assessment of endemism and species richness patterns in the Australian Anura

Aim To assemble a continental‐scale data set of all available anuran records and investigate trends in endemism and species richness for the Anura. Location Continental Australia. Methods 97,338 records were assembled, covering 75% of the continent. A neighbourhood analysis was applied to recorded locations for each species to measure richness and endemism for each half‐degree grid square (c. 50 km) in the continent. This analysis was performed for all anurans, and also for each of the three main anuran families found in Australia. A Monte Carlo simulation was used to test a null hypothesis that observed centres of endemism could result simply from an unstructured overlapping of species ranges of different sizes. Results Eleven main centres of anuran endemism were identified, the most important being the Wet Tropics and the south‐west near Bunbury‐Augusta and near Walpole. With the exception of south‐western Australia, all of the identified significant endemic centres are in the northern half of the continent. The regions identified as significant for endemism differed from those identified for species richness and are more localized. Species richness is greatest in the Wet Tropics and the Border Ranges. High species richness also occurs in several areas not previously identified along the east and northern coasts. Main conclusions Weighted endemism provides a new approach for determining significant areas for anuran conservation in Australia and areas can be identified that could be targeted for beneficial conservation gains. Patterns in endemism were found to vary markedly between the three main anuran families, and south‐eastern Australia was found to be far less significant than indicated by previous studies. The need for further survey work in inland Australia is highlighted and several priority areas suggested. Our results for species richness remain broadly consistent with trends previously observed for the Australian Anura.     

Species Account of Anura ns from the Western Slope of Mt. Kita nglad,Mindanao Island,Philippines

The Mt. Kitanglad Range is one of the country’s important key biodiversity sites;however, information about anuran diversity in this protected area remains depauperate. Herein we provided accounts of anuran species from high-elevation forests, in three sites of the western slope of Mt. Kitanglad range. The combined belt-transect sampling and microha bitat searches accounted for 13 species representing five families. The most represented family was Rhacophoridae with five representative species of the genus Philautus. Twelve out of the 13 species documented in the current survey are endemic. Four previously unaccounted species(Pelophr yne brevipes, Pulchrana grandocula, Sanguirana mearnsi, and Philautus surrufus) were added and brought the total anurans known from Mt. Kitanglad to 26 species. Most of the species were also recorded in forested sites, suggestive of their lesser affinity to non-forested ecosystems. The additional species detected during our survey may also imply that full understanding of anuran diversity of Mt. Kitanglad remains far from complete.     

Morphological and life history responses to predators in larvae of seven anurans

Amphibian larvae often face two major sources of mortality: pond desiccation and predation. Tadpoles of seven anuran species with different preferences for type of breeding habitat, on a hydroperiod scale, were tested for responses to the presence of predators by raising them experimentally in the presence and absence of a separately caged invertebrate predator that was fed on conspecific tadpoles. The species typically breeding in temporary or semi-permanent ponds ( Rana temporaria , Rana arvalis , Rana dalmatina and Hyla arborea ) – where invertebrate predator populations are predicted to vary considerably spatiotemporally – all showed marked induced increases in tail fin depth in response to predator presence. These species also tended to respond by reduced growth rates. The representative of the most ephemeral habitats, Bufo calamita , did not respond in any of these traits. Its congeneric, Bufo bufo , a toxic inhabitant of permanent ponds and lakes, tended to respond to predator presence by reducing its growth rate, though not by a tail depth increase. I argue that the rather poor swimming performance in Bufo tadpoles may opt for defences other than locomotor ability. The palatable, permanent pond species Pelobates fuscus did not alter either its growth rate or tail morphology. Possible explanations for this result are discussed.     

PHYLOGENETIC ANALYSES REVEAL UNEXPECTED PATTERNS IN THE EVOLUTION OF REPRODUCTIVE MODES IN FROGS

Understanding phenotypic diversity requires not only identification of selective factors that favor origins of derived states, but also factors that favor retention of primitive states. Anurans (frogs and toads) exhibit a remarkable diversity of reproductive modes that is unique among terrestrial vertebrates. Here, we analyze the evolution of these modes, using comparative methods on a phylogeny and matched life‐history database of 720 species, including most families and modes. As expected, modes with terrestrial eggs and aquatic larvae often precede direct development (terrestrial egg, no tadpole stage), but surprisingly, direct development evolves directly from aquatic breeding nearly as often. Modes with primitive exotrophic larvae (feeding outside the egg) frequently give rise to direct developers, whereas those with nonfeeding larvae (endotrophic) do not. Similarly, modes with eggs and larvae placed in locations protected from aquatic predators evolve frequently but rarely give rise to direct developers. Thus, frogs frequently bypass many seemingly intermediate stages in the evolution of direct development. We also find significant associations between terrestrial reproduction and reduced clutch size, larger egg size, reduced adult size, parental care, and occurrence in wetter and warmer regions. These associations may help explain the widespread retention of aquatic eggs and larvae, and the overall diversity of anuran reproductive modes.     

ABNORMAL MIGRATION AND HYBRIDIZATION OF LARUS ARGENTATUS AND L. FUSCUS AFTER INTERSPECIES FOSTERING EXPERIMENTS

Between 1962 and 1966 eggs of Larus argentatus and L. fuscus were interchanged andalmost 900 young were reared by the wrong species. Many of these cross-fostered young were later recovered or retrapped on and away from the colonies.
The British population of argentatus is sedentary and ringed birds are not recovered outside Britain, whereas fuscus normally migrates. Many cross-fostered argentatus migrated to France, Spain and Portugal, areas where fuscus is common, but they did not migrate as far as the control fuscus . It is possible that these cross-fostered argentatus had followed their foster parents when these migrated, but this is unlikely as the cross-fostered fuscus also migrated although their foster parents would have remained in Britain.
Despite wide ecological and behavioural overlaps, interbreeding between L. argentatus and L.fuscus is exceedingly rare. However, as a result of cross-fostering experiments, 31 and 40 mixed pairs were found on Skokholm in 1968 and 1969 respectively. Although some of the birds involved were unringed it is probable that all the adults in mixed pairs had been cross-fostered. Other cross-fostered birds were found mated with their own species and it appears that the sex of the imprinted birds was important. Female gulls will usually only mate with males of their own species, or in the case of the cross-fostered birds, with males of their foster species. Males will mate with either species.
Evidence is given that suggests that the colour of the mantle and wings is important in species recognition at long range, and the colour of eye-ring and join of the mandibles for recognition at short range. The role of voice is uncertain but general behaviour is probably unimportant.