Larval morphology, vocalisations, and phylogenetic position of Crossodactylus dantei (Anura: Hylodidae): new insights into a little-known anuran species

The advertisement call contains important spectral and temporal information for species-specific recognition and is generally related to sexual attraction. On the other hand, the territorial call is emitted to defend a specific territory from conspecifics or heterospecifics. Therefore, we hypothesised that the territorial call of sympatric and close related species is more similar to each other (as a result of convergence or lack of divergence) than their advertisement calls. In order to test this hypothesis, we examined the territorial and advertisement calls of five anuran species of the genus Scinax. These species are sympatric and two of them were previously observed displaying heterospecific territorial communication. We redescribed the advertisement and territorial calls of these five species, compared them with cluster analyses and found that acoustic characteristics of the territorial calls were more similar to each other than that of their advertisement calls. These results could be indicative of a convergent selective pressure for the territorial call in opposite to a divergent selective pressure for the advertisement call. This pattern may be more widespread than reported and future directions are proposed.

Vocalization is an important means of intra- and interspecific communication in anurans and is essential for reproduction. Here, we describe the advertisement and territorial calls of Pithecopus rusticus and determine the influence of air temperature and morphometric variables on advertisement call parameters. We recorded the vocalizations at the type-locality, in the municipality of Agua Doce, state of Santa Catarina, southern Brazil, from September 2015 to February 2016. The advertisement call was composed of a short note, emitted sporadically, with a duration of 0.023 ± 0.002 ms (0.019–0.033 ms; n = 244). We recorded two types of territorial calls that were observed during the interaction between males. Territorial call I was composed of two notes and had a duration of 0.095 ± 0.043 ms (0.033–0.166 ms; n = 27). Territorial call II was a multipulsed note lasting 0.911 ± 0.340 ms (0.504–1.346 ms; n = 9) composed of 7–58 pulses emitted after territorial call I. Advertisement call duration was negatively related to air temperature. The duration and number of notes of the advertisement call of P. rusticus were similar to those of phylogenetically close species. Information on vocal repertoires of amphibians and factors influencing acoustic parameters are essential to understand the systematic taxonomy and evolution of groups, especially little-known species such as P. rusticus.

We describe the advertisement and territorial calls of Hylodes meridionalis for the first time and provide observations on nocturnal calling activity for this species. The advertisement call has 36–82 harmonic notes, with duration of 2.71–5.69 s and dominant frequency on the third harmonic. Advertisement calls are separated by large intervals varying from 18.7 to 44.7 s. The territorial call has 1–3 notes, with duration of 0.039–0.567 seconds, and dominant frequency also on the third harmonic. Territorial calls are emitted at a much higher repetition rate than the advertisement call, with intervals of 1.1–1.6 s between each call. Frogs of the genus Hylodes are known to call mainly during the day, but for H. meridionalis nocturnal calling was observed on various occasions, and could occur regularly until two hours after sunset, or sporadically along the night. Descrevemos os cantos de anúncio e territorial de Hylodes meridionalis pela primeira vez e fornecemos observações sobre a atividade noturna de vocalização para esta espécie. O canto de anúncio tem 36–82 notas harmônicas, com duração de 2,71–5,69 segundos e frequência dominante no terceiro harmônico. Há grandes intervalos entre os cantos de anúncio, de 18,7–44,7 segundos. O canto territorial tem 1–3 notas, com duração de 0,039–0,567 segundos, e frequência dominante também no terceiro harmônico. Cantos territoriais são emitidos a uma taxa de repetição muito mais elevado do que o canto de anúncio, com intervalos de 1,1–1,6 segundos entre cada canto. As espécies do gênero Hylodes são conhecidas por vocalizar principalmente durante o dia, mas machos de H. meridionalis foram observados em atividade de vocalização noturna em várias ocasiões, sendo que podem vocalizar regularmente até duas horas após o pôr do sol, ou esporadicamente ao longo da noite.

In this study we analysed the acoustic activity of Hylodes heyeri in areas of Atlantic Forest, in southern Brazil. Observations were made in November 2001 and from January to April 2002, at Estação II Instituto Agronômico do Paraná, municipality of Morretes, State of Paraná. Males displayed three different vocalizations: advertisement calls, territorial calls, and courtship calls. Temporal and spectral parameters of advertisement and territorial calls were analysed, along with call intensity. The duration of the advertisement call showed a negative correlation with air temperature, with males decreasing the duration of advertisement calls at higher temperatures. Male body size was not correlated with any of the acoustic parameters. Details on habitat use, distances to nearest vocalizing neighbour, and daily calling activity are also included.

Abstract. Communication in anurans is mostly mediated by acoustic signals. Depending on the type of social interactions, different call types can be displayed by anurans. The main function of advertisement calls is to attract females, which prefer males whose advertisement calls have high repetition rates. Conversely, territorial calls are used to defend territories. We described the advertisement and territorial calls of Bokermannohyla sapiranga (n = 25 individuals), Hypsiboas albopunctatus (n = 21 individuals) and H. goianus (n = 57 individuals) from the Silvânia National Forest, Cerrado. We tested the hypothesis that advertisement and territorial calls are emitted under different social contexts and are, therefore, structurally distinct. We also assessed the influence of air temperature on call rates. We made recordings during reproductive (spontaneous formation of chorus) and aggressive (presence of intruder male) contexts. To simulate the presence of potential rivals we exposed males to acoustic (aud...

The use of acoustic signals is a common characteristic of most anuran species to mediate intraspecific communication. Besides many social purposes, one of the main functions of these signals is species recognition. For this reason, this phenotypic trait is normally applied to taxonomy or to construct evolutionary relationship hypotheses. Here the acoustic repertoire of five populations of the genus Allobates from the Brazilian Atlantic Forest are presented for the first time, on a vulnerable to extinction Neotropical taxon. The description of males’ advertisement and aggressive calls and a female call emitted in a courtship context are presented. In addition, the advertisement calls of individuals from distinct geographical regions were compared. Differences in frequency range and note duration may imply in taxonomic rearrangements of these populations, once considered distinct species, and more recently, proposed as a single species, Allobatesolfersioides. Calls of the male from the state of Rio de Janeiro do not overlap spectrally with calls of males from northern populations, while the shorter notes emitted by males from Alagoas also distinguishes this population from the remaining southern populations. Therefore, it is likely that at least two of the junior synonyms should be revalidated. Similarities among male advertisement and female calls are generally reported in other anuran species; these calls may have evolved from a preexisting vocalization common to both sexes. Male aggressive calls were different from both the male advertisement and female calls, since it was composed by a longer and multi-pulsed note. Aggressive and advertisement calls generally have similar dominant frequencies, but they have temporal distinctions. Such patterns were corroborated with the Atlantic Forest Rocket Frogs. These findings may support future research addressing the taxonomy of the group, behavioral evolution, and amphibian conservation.

We describe a new species of Cycloramphus of the eleutherodactylus group from the Ilha dos Alcatrazes, southeastern Brazil, with descriptions of advertisement and territorial calls and notes on natural history. Additionally, we describe the advertisement and territorial calls of C. eleutherodactylus. The new species is diagnosed by the following set of characters: snout truncate in lateral and dorsal views; head wider than long; eyes protruding; tibia shorter than thigh; and distinct advertisement call. The new species is known from a single population on the Ilha dos Alcatrazes, a 149 ha island about 35 km off São Paulo State coast where these frogs are scattered in a small valley. The very restricted range of the new species of Cycloramphus and the declining quality of its habitat qualify this frog as critically endangered.

Although courtship vocalizations are unique to each species, the basic architecture of the neural circuitries underlying this behavior is conserved among closely related species of frogs, suggesting behavior can diverge while utilizing the homologous neural network inherited through evolutionary lineage.

Anurans communicate using a repertoire of acoustic signals that can be classified as different call types based on differences in both their acoustic properties and the contexts in which they are produced. Descriptions of these repertoires represent a key first step towards understanding the vocal behaviour of any species and provide a critical foundation for comparative bioacoustic studies. In this study of the olive frog, Babina (formerly Rana) adenopleura, a territorial species from subtropical Taiwan, we used focal observations, acoustic recordings and statistical analyses of temporal, spectral and amplitude-related call properties to describe six different call types in the species' vocal repertoire. These call types included a putative advertisement call, territorial call, encounter call, amplectant call, distress call and alarm call. Advertisement calls consisted of four to five discrete notes, and they were the most commonly produced call. Territorial and encounter calls were delivered during interactions with other males; the former is a two-note call, whereas the latter is a distinctly pulsatile signal. Amplectant calls were acoustically similar to territorial calls but were delivered while males were in amplexus. Distress calls were given while the animal was being consumed by a snake, and alarm calls were recorded in response to startling stimuli. With basic descriptions of these call types in hand, we discuss several testable hypotheses for their putative adaptive functions.

One of the most important resources for reproduction in frogs is the acoustic space since the advertisement call, which is mostly used to attract females, may suffer interference when the acoustic space is widely filled. Other important resources are calling sites and adequate climatic conditions. We analyzed herein three dimensions of the acoustic niche of anurans (advertisement calls, calling period, and calling sites). We recorded 11 calling species of frogs in a tropical community. Species richness was negatively related to temperature, and daily activity was positively related to humidity. We also observed a greater niche overlap than expected by chance in calling periods. These results indicate that the climatic conditions should act as an environmental filter, synchronizing the calling period. The calling site was not shared among species, and no clear pattern of substrate use was observed. Regarding the acoustic dimension, we observe a phylogenetic signal in the dominant frequency of advertisement calls. Hierarchical cluster analysis also indicated a congruence between acoustic distances and phylogenetic relationships. Therefore, the dominant frequency of advertisement calls was constrained by phylogenetic relationships, indicating that it affects the partitioning and use of acoustic resources, an important dimension in reproductive activity in anurans.

We describe a new species of treefrog from the ruber clade of the genus Scinax, from Serra do Cabral, State of Minas Gerais, Brazil. Scinax cabralensis is characterized by a small size, slightly arched and faintly distinct canthus rostralis, spotted pattern of coloration on dorsum, thighs with transversal bars, granular skin on dorsum and venter, rounded snout in dorsal view, and distinct advertisement call. Additionally, data on advertisement and territorial calls and notes on natural history and habitat are provided.

We describe a new species of litter frog from western Brazilian Amazon previously referred to as Allobates femoralis (Boulenger 1883). The new species is allopatric to A. femoralis and its known occurrence is restricted to terra-firme forests on the left bank of the upper Madeira River and southeastern State of Acre. This species is distinguished from A. femoralis and from other species in the A. femoralis group by presenting two-note advertisement calls and conspicuous reddish-orange color on ventral surfaces of hind limbs and posterior abdomen. Phylogenetic analyses based on a fragment of the 16S rRNA mitochondrial gene suggest the new species is the sister group to a clade referred to as A. femoralis occurring in southern State of Acre, from which it is distinguished by six unambiguous nucleotide substitutions, in addition to exclusive advertisement calls and color patterns. The new species is more distantly related to A. femoralis sensu stricto occurring near the A. femoralis type locality in the Peruvian Amazon. Summarizing evidence from molecular phylogenetic analysis, genetic distances and available data on advertisement calls, we identify one possible case of genetic introgression between lineages in this group and highlight the potential for the description of more species within the A. femoralis complex.

We describe a new species of the Dendropsophus leucophyllatus Group from the Atlantic Forest of the southern region of State of Bahia, Brazil. It can be distinguished from all species of the D. leucophyllatus Group on the basis of morphological characters (especially its unique dorsal pattern and snout in dorsal view), advertisement calls and divergence in mitochondrial DNA gene sequences. The inclusion of D. anceps on the group remains controversial but our phylogenetic analyses do not recover the new species as sister to syntopic species of the D. leucophyllatus Group (with or without D. anceps). These results also highlight the palimpsest that is past relation between the Atlantic and Amazon forests.

Background. Brachycephalus includes miniaturized frogs with restricted geographical distributions throughout the Brazilian Atlantic Forest. Ecological data for most species are still scarce. For instance, advertisement calls have only been described for 12 of the 36 known species, including B. tridactylus, a recently described species from southern Brazil. Posteriorly, features of the advertisement call of B. tridactylus were compared with congeners and the unique characteristics of its call were highlighted. To confirm these potentially divergent characteristics, we reanalysed an original recording of B. tridactylus and analysed our own recordings and verified that the original description of its advertisement call is inaccurate. Thus, we redescribe its advertisement calls. Methods. We asked the descriptors of B. tridactylus the original recordings that they made and requested access to the only original recording deposited in a collection of sounds. We received from André Lima a copy of one recording, the same as the one that had deposited, and obtained permission to re-analyze it. We studied this recording and compared it with our own recordings, made at the type locality of the species on March, 2016. Sound samples were analysed with Raven Pro 1.5.0 and call analyses were made under a note-centered approach. Results. The original recording was amplified somehow by at least 6 dB and was also clearly low-pass filtered with a cutoff frequency of 10 kHz. Our analyses did not allow us to recognize several of the acoustic parameters normally described in Brachycephalus. The sound we heard from the notes overlapped with other signals (noise?), which prevented us from clearly determining the end of the note and other important features, such as the presence of pulses. According to our recordings (n = 15 individuals), B. tridactylus emitted a relatively long advertisement call (50.8 s, on average), composed by 10–13 notes emitted in a note rate of 3.7–8.3 notes per minute. Only isolated notes were present. The notes were composed by 1–3 pulses and the note duration varied from 0.002–0.021 s. Discussion. The original description of the call of B. tridactylus is incorrect because it included background noise and amplification artefacts as part of the call parameters. However, we recognize that the original recording and our recordings have captured the same type of call. In our measurements of the species calls, note duration was nearly an order of magnitude shorter as the original description. The existence of notes with 1–3 pulses was not acknowledged in the original description. With few pulses per notes, the advertisement call of B. tridactylus is distinct from the notes with several pulses of B. ephippium, B. pitanga, B. crispus, B. sulfuratus, and B. darkside. The advertisement calls of B. tridactylus is also distinct from that of B. albolineatus and B. mirissimus by having only isolates notes, instead of isolated notes and note groups.

We describe the tadpole morphology, the advertisement and courtship calls, and reproductive characteristics of Rupirana cardosoi Heyer 1999, an endemic species from rocky mountain fields in Chapada Diamantina, Bahia State, Brazil. Females of Rupirana cardosoi deposit pigmented eggs in shallow backwaters or ponds. The body of tadpoles is ovoid in dorsal and ventral views and depressed in lateral view. The oral disc is ventral and the labial tooth row formula is 2(2)/3(1). Eyes are dorsal. The advertisement call has one pulsed note, with dominant frequency approximately 1.3 kHz. The courtship call presents three note types with dominant frequency ranging from 0.7 to 1.4 kHz. Females are larger ( = 34.4, SD = 1.6, 31.4–37.4 mm, n = 12) than males ( = 30.9, SD = 1.5, 28.8–33.8, n = 9; t = 5.1; p < 0.001) and males present nuptial excrescences located on the base of the thumbs. The eggs are medium sized ( = 2.47 ± 0.52 mm, N = 27) and mean clutch size was 120.44 ± 74.38 eggs (N = 11 clutches).