Advertisement Call Variation in the Golden Rocket Frog (Anomaloglossus beebei): Evidence for Individual Distinctiveness

Individual distinctiveness in acoustic signals can allow receivers to respond appropriately to different individuals. The aim of this research was to examine signal variation and to investigate the relative importance of different acoustic properties for coding individual distinctiveness in the advertisement calls of male golden rocket frogs (Anomaloglossus beebei). We examined patterns of within‐individual and among‐individual variability in 760 advertisement calls of 40 males as well as repeatability in 16 additional males that were recorded on two different occasions. We examined eight call properties, and all properties exhibited significant among‐individual variation and moderate to high repeatability across days. We employed discriminant function analysis to examine individual distinctiveness statistically. These analyses assigned 79% of calls to the correct individual. Fine temporal properties, including pulse duration, pulse rate, and pulse interval, as well as the spectral property of dominant frequency, contributed most toward discrimination among individuals. These results indicate that individual male golden rocket frogs can be distinguished statistically by their advertisement calls. We use these findings to evaluate results of previous playback studies in A. beebei and to generate testable predictions regarding the potential for specific call properties to function in mate selection and social recognition.     

Crossing the Tasman Sea: Inferring the introduction history of Litoria aurea and Litoria raniformis (Anura: Hylidae) from Australia into New Zealand

Abstract The amphibian fauna of New Zealand consists of three native species (Leiopelma spp.), and three Litoria species introduced from Australia in the last 140 years. We conducted a molecular phylogeographical study that aimed to identify the Australian origins of two species, Litoria aurea and Litoria raniformis. We used partial sequences of the mitochondrial cytochrome oxidase I (cox1) gene from 59 specimens sampled from across the range of both species to identify the probable source populations for the New Zealand introductions, and to describe the current genetic diversity among New Zealand Litoria populations. Our genetic data suggest that L. aurea was introduced into the North Island of New Zealand from two regions in Australia, once from the northern part of coastal New South Wales and once from the southern part of coastal New South Wales. Our data indicate that L. raniformis introductions originated from the Melbourne region of southern Victoria and once established in the South Island of New Zealand, the species subsequently spread throughout both islands. In addition, we found a distinct haplotype in L. raniformis from Tasmania that strongly suggests, contrary to earlier reports, that this species was not introduced into New Zealand from Tasmania. Finally, we identified two very distinctive mitochondrial lineages of L. raniformis within the mainland Australia distribution, which may be previously unrecognized species.     

Comparative skeletogenesis of the Oriental Tree Frog Hyla orientalis (Anura: Hylidae)

The ontogeny of skeletal development of the Oriental Tree Frog, Hyla orientalis (Bedriaga, 1890), is followed from tadpole to froglet and compared with four other hylid species i.e., Hypsiboas lanciformis, Hypsiboas pulchellus, Phyllomedusa vaillanti and Pseudis platensis. Our analysis and comparison is based on cleared and double-stained specimens. The parasphenoid is the first skeletal element that ossified in Hyla orientalis is followed by the exoocipital, prootic, axial and appendicular skeletal elements, frontoparietal, nasal, upper jaw, squamosal, pterygoid, lower jaw, vomer and quadratojugal. Ossification initiated at early Stage 33 in Hyla orientalis whereas in other hylids it begins after Stage 37. Major transformations of the larval jaw were visible after Stage 42. Cranial ossifications were completed after appendicular and axial ossifications of Hyla orientalis. All skeletal elements ossified before the end of the metamorphosis, a unique feature of Hyla orientalis in comparison to the other hylids studied here.     

Functional anatomy of the internal gills of the tadpole of Litoria ewingii (Anura,Hylidae)

Summary (1) Scanning electron microscopy and vascular casting were used to study the morphology and vascular anatomy of the fully developed internal gills of Litoria ewingii tadpoles. — (2) The four pairs of gills were located in two branchial baskets on either side of the heart. Each gill consisted of a branchial arch with gill tufts projecting ventrally and gill filters running dorsally. The gills bore a variable number of gill tufts in which a complex three-dimensional array of capillary loops, of varying lengths and diameters, was trailed in the path of the ventilatory current. — (3) The evidence presented in this paper suggests that the gill tufts have greater potential as gas exchangers than either the gill filters or skin. — (4) The study revealed structural and functional evidence for the existence of branchial shunts between afferent and efferent branchial arteries.     

The Fine Structure of the Cortex of the Protist Protoopalina australis (Slopalinida, Opalinidae) from Litoria nasuta and Litoria inermis (Amphibia: Anura: Hylidae) in Queensland, Australia

ABSTRACT. The ultrastructural appearance of cortical structures of Protoopilina australis is described. With respect to kinetosomal architecture and the supports of the surface folds, Protoopalina australis has an ultrastructural identity similar to other opalines. However, microfibrillar tracts and regular arrays of cortical vesicles—evident in Opalina and Cepedea —are absent from the binucleate genera. This new insight, combined with the recent discovery of a new genus ( Protozelleriella ) is used to revise our understanding of the evolution of slopalines and we favour a common origin for the multinucleate genera Opalina and Cepedea.     

Differential Evolution of Advertisement Call Traits in Dart-Poison Frogs (Anura: Dendrobatidae)

The ability to recognise and discriminate between heterospecific and conspecific individuals plays an essential role in mate choice, reproductive isolation and thus species diversification. Many animals discriminate based on advertisement calls, whose evolution may be driven by a variety of forces such as natural selection, sexual selection or stochastic processes. The relative importance of stochastic processes acting on a given trait is usually correlated with its phylogenetic signal. Mate-recognition signals are complex traits composed of multiple features that could potentially respond independently to evolutionary forces. The advertisement call of anurans is used in species recognition and mate choice. In this study, we estimate the phylogenetic signal for body size and a suite of traits describing the male advertisement call from dart-poison frogs (Anura: Dendrobatidae). We found a surprisingly high phylogenetic signal for all call traits. In addition, call traits varied in their degree of phylogenetic signal, suggesting that evolutionary forces have been acting differently on different traits. Pulse duration showed the strongest phylogenetic signal. Peak frequency and body size were correlated and presented high phylogenetic signal indicating that the evolution of one trait may be driving or constraining the other. Since most variation in call traits can be explained by the phylogenetic history of the species, we cannot reject the hypothesis that stochastic processes account for significant evolutionary divergence in frog calls.     

Low Phylogeographic Structure in a Wide Spread Endangered Australian Frog <Emphasis Type="Italic">Litoria aurea</Emphasis> (Anura: Hylidae)

The green and golden bell frog (Litoria aurea) has a widespread distribution along the south-east coast of Australia. The species range, however, is highly fragmented and remaining populations are predominately isolated and restricted to the coastline. Previously, the range extended further inland and the species was considered common. Here we report a study designed to identify the phylogeographic and conservation genetic parameters of L. aurea. Mitochondrial DNA sequences were examined from 263 individuals sampled from 26 locations using both phylogenetic and population analyses. Despite a general consensus that amphibians are highly structured we found no phylogeographic divisions within the species, however, there was significant structure amongst extant populations (F _ST=0.385). Patterns of haplotype relatedness, high haplotypic diversity (mean h=0.547) relative to low nucleotide diversity (mean π=0.003) and mismatch distribution analysis supported a Pleistocene expansion hypothesis with continued restricted dispersal and gene flow. We conclude that the genetic structure of the species may permit ‘well managed’ intervention to mediate gene flow amongst isolated populations and provide some guidelines for the implementation of such conservation strategies.     

Geographic and Temporal Variation of the Male Zebra Finch Distance Call

Temporal and geographic variation of acoustic signals can provide insights into dispersal patterns, population history and speciation. Vocalizations that are transmitted from one generation to the next are of particular value in this respect because they can reveal patterns of gene flow, effectively behaving as population markers. The male zebra finch Taeniopygia guttata distance call is one such vocalization; sons learn their father's distance call in the first 40 d of life and it is individually stereotyped thereafter. We investigated geographic variation in the zebra finch by comparing the structure of distance calls recorded from 61 males from six populations across the continent‐wide range of the Australian subspecies T. g. castanotis. Intra‐population variation was high, in many cases greater than the variation among all males recorded, possibly because of population interchange. However, three of six call variables measured, including the newly discovered modulated element, varied geographically although the pattern of distance call variation did not agree with that of geographic proximity of populations. The proportion of calls with a modulated element increased dramatically over 7 yr in central Australia but there was no change over a similar period of time in south‐eastern Australia where no calls contained the element. The findings suggest that interchange among widely separated populations may be commonplace in Australian zebra finches, with the possible exception of those from south‐eastern Australia.     

A cladistic analysis of Scinax (Anura: Hylidae)

The hylid frog genus Scinax ranges from southern Mexico to eastern Argentina. The 84 recognized species are currently arranged in five groups: the Scinax rubra , Scinax rostrata , Scinax catharinae , Scinax staufferi , and Scinax perpusilla species groups. Although a few species groups are distinctive, compelling evidence of monophyly is lacking for three groups, and their interrelationships remain virtually unknown. With the objective of testing the monophyly of the species groups and exploring their interrelationships, a cladistic analysis was performed, employing 86 characters from osteology, myology, adult and larval external morphology, reproductive biology, and karyotypes taken from 36 representative species of the five species groups plus eight outgroup taxa. The analysis of the resulting data matrix shows moderately well-supported (as assessed through Bremer support and parsimony jackknifing) S. catharinae and S. rostrata species groups. The S. staufferi species group is polyphyletic, as currently composed, given that some of its species are nested within the S. catharinae species group. The only representative of the S. perpusilla species group is the sister species of the S. catharinae species group. Although weakly supported, the representatives of the S. rostrata and S. staufferi species groups are nested, separately, within the S. rubra species group. In order to have a taxonomy consistent with these results, it is proposed not to recognize the S. rubra group but to recognize a more inclusive rubra clade that includes all studied exemplars of the former S. rubra group, plus some of the S. staufferi group and all of the S. rostrata group. Similarly, a catharinae clade is recognized, within which all studied exemplars of the S. catharina e group (that now includes Scinax berthae and Scinax agilis ) and the one studied representative of the S. perpusilla group are included.     

The phylogeny of Dendropsophini (Anura: Hylidae: Hylinae)

The relationships of the hyline tribe Dendropsophini remain poorly studied, with most published analyses dealing with few of the species groups of Dendropsophus. In order to test the monophyly of Dendropsophini, its genera, and the species groups currently recognized in Dendropsophus, we performed a total evidence phylogenetic analysis. The molecular dataset included sequences of three mitochondrial and five nuclear genes from 210 terminals, including 12 outgroup species, the two species of Xenohyla, and 93 of the 108 recognized species of Dendropsophus. The phenomic dataset includes 46 terminals, one per species (34 Dendropsophus, one Xenohyla, and 11 outgroup species). Our results corroborate the monophyly of Dendropsophini and the reciprocal monophyly of Dendropsophus and Xenohyla. Some species groups of Dendropsophus are paraphyletic (the D. microcephalus, D. minimus, and D. parviceps groups, and the D. rubicundulus clade). On the basis of our results, we recognize nine species groups; for three of them (D. leucophyllatus, D. microcephalus, and D. parviceps groups) we recognize some nominal clades to highlight specific morphology or relationships and facilitate species taxonomy. We further discuss the evolution of oviposition site selection, where our results show multiple instances of independent evolution of terrestrial egg clutches during the evolutionary history of Dendropsophus.     

Meiotic chromosomes of the tree frog Smilisca baudinii (Anura: Hylidae)

The Mexican tree frog Smilisca baudinii, is a very common frog in Central America. In spite their importance to keep the ecological equilibrium of the rainforest, its biology and genetics are poorly known. In order to contribute with its biological knowledge, we described the typical meiotic karyotype based in standard cytogenetic protocols to specimens collected in Tabasco, Mexico. The study was centered in the analysis of 131 chromosome spreads at meiotic stage from two adults of the species (one female and one male). The metaphase analysis allowed the establishment of the modal haploid number of 1n = 12 bivalent chromosomes. The chromosomic formulae from the haploid bivalent karyotype was integrated by 12 biarmed chromosomes characterized by twelve pairs of metacentric-submetacentric (msm) chromosomes. The meiotic counting gives the idea that diploid chromosome number is integrated by a complement of 2n = 24 biarmed chromosomes. The presence of sex chromosomes from female and male meiotic spreads was not observed. Current results suggest that S. baudinii chromosome structure is well shared among Hylidae family and "B" chromosomes are particular structures that have very important evolutionary consequences in species diversification.     

Observations on the polyphyodont dentition of Hemiphractus proboscideus (Anura: Hylidae)

In Hemiphractus fang–like teeth are ankylosed to the premaxilla, maxilla and prevomer, and bony odontoids are found on the dentary, angular and palatine bones. The odontoids are small, but a larger pair at the front of the lower jaw project upwards and backwards into the mouth and fit into a diastema between the anterior premaxillary teeth when the mouth is closed.
The teeth are unipartite and monocuspid, and each consists of a strongly recurved and elongated cone of orthodentine, capped at the tip by a thin layer of enamel. The inner circumpulpal layer of the dentine is tubular, but no tubules are present in the outer pallial layer. During tooth development, dentine is formed before the enamel matrix is produced, and the tooth germs lie horizontally beneath the ventral surface of each dentigerous bone. On eruption, the tooth germs migrate horizontally and become ankylosed to the outer edge of the jaw bone by a layer of cellular cementum.
During tooth replacement, the vast majority of the dentine of each tooth, and the cementum at the tooth base, are resorbed by osteoclasts. It is not clear whether the tips of the teeth are shed or not.     

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.