Advertisement call of Brachycephalus albolineatus (Anura: Brachycephalidae)

Abstract

Background. Brachycephalus are among the smallest terrestrial vertebrates in the world. The genus encompasses 34 species endemic to the Brazilian Atlantic Rainforest, occurring mostly in montane forests, with many species showing microendemic distributions to single mountaintops. It includes diurnal species living in the leaf litter and calling during the day, mainly during the warmer months of the year. The natural history of the vast majority of the species is unknown, such as their advertisement call, which has been described only for seven species of the genus. In the present study, we describe the advertisement call of Brachycephalus albolineatus, a recently described microendemic species from Santa Catarina, southern Brazil. Methods. We analyzed 34 advertisement calls from 20 individuals of B. albolineatus, recorded between 5–6 February 2016 in the type locality of the species, Morro Boa Vista, on the border between the municipalities of Jaraguá do Sul and Massaranduba, Santa Catarina, southern Brazil. We collected five individuals as vouchers (they are from the type series of the species). We used the note-centered approach sensu Köhler et al. (2017) to describe the advertisement calls of the species. Results. Brachycephalus albolineatus have a long advertisement call of 40–191 s (mean of 88 s) composed of 7–26 notes (mean of 14 notes) emitted at a rate of 6–13 notes per minute (mean of 9 notes per minute) and at a note dominant frequency of 5–7 kHz (mean of 6 kHz). Advertisement calls are composed of isolated notes and note groups (two notes involved in each particular note group); the former is composed by one to three pulses (mean of 2.0) and the note groups by two or three pulses in each note (mean of 2.7). Most advertisement calls present both isolated notes and note groups, with a few cases showing only the former. Note groups are emitted invariably in the last third of the advertisement call. Most isolated notes escalate their number of pulses along the advertisement call (1 to 2, 1 to 3 or 2 to 3). Note duration of isolated notes varies from 0.002–0.037 s (mean of 0.020 s) and duration of note group vary from 0.360–0.578 s (mean of 0.465 s). Discussion. Individuals increase the complexity of their calls as is proceeds, incorporating note groups and pulses per note. Intra-individual variation analysis also demonstrated that less structured advertisement calls (i.e. with notes with fewer pulses) are not stereotyped. It is possible that isolated notes and note groups could have distinct function, perhaps territorial defense and mating, respectively. We believe that using a note-centered approach facilitates comparisons with calls of congeners, as well as underscores the considerable differences in call structure between species in a single group and among species groups.

Redescription of the advertisement call of Brachycephalus tridactylus (Anura: Brachycephalidae)

“…Short notes are characteristic of all species of the Brachycephalus pernix Group, which includes species from southern Brazil. The mean note lengths of this group are, as follow: 0.010 s for B. mirissimus (Pie et al 2018); 0.012 s for B. tridactylus (this study); 0.020 s for B. albolineatus (Bornschein et al 2018); 0.04 s for B. actaeus (Monteiro et al 2018a); 0.04 s for B. olivaceus (Monteiro et al 2018b); and 0.05 s for B. quiririensis (Monteiro et al 2018b). Pulsed notes are characteristic of all species of Brachycephalus (compilations in Monteiro et al 2018a,b, Pie et al 2018, and this study).…”

“…Likewise, we adopted the general presentation order and particularities in Köhler's parameters, as presented in Bornschein et al (2018). We considered all parameters used in describing the call of Brachycephalus albolineatus (Bornschein et al 2018), but we used only those applicable to the call characteristics of B. tridactylus, as follow: (1) call duration (s); (2) note rate (notes per min); (3) number of notes per call; (4) number of pulses per notes; (5) note duration (s); (6) inter-note interval (s); (7) note dominant frequency (kHz); (8) highest frequency (kHz); and (9) lowest frequency (kHz). Call duration is defined as the time span from the beginning of the first note to the end of the last note emitted in a call.…”

“…; Bornschein et al 2016). Although all species are diurnal and locally abundant (Bornschein et al 2018), they are difficult to find owing to their restricted ranges and microendemism. In the last decade, intensified fieldwork has led to the description of 23 species (Frost 2018), but data on natural history lag behind the rate of new species descriptions.…”

“…In the last decade, intensified fieldwork has led to the description of 23 species (Frost 2018), but data on natural history lag behind the rate of new species descriptions. Advertisement calls have been described for 12 of 36 species (33%): B. actaeus Haddad, 2018 (Monteiro et al 2018a); B. ephippium (Spix, 1824) (Pombal et al 1994, Goutte et al 2017; B. albolineatus Bornschein, Ribeiro, Blackburn, Stanley, andPie, 2016 (Bornschein et al 2018); B. crispus Condez, Clemente-Carvalho, Haddad, andReis, 2014 (Condez et al 2014); B. darkside Guimarães, Luz, Rocha, andFeio, 2017 (Guimarães et al 2017); B. hermogenesi (Giaretta and Sawaya, 1998) (Verdade et al 2008); B. mirissimus Pie, Ribeiro, Confetti, Nadaline, andBornschein, 2018 (Pie et al 2018); B. olivaceus Bornschein, Morato, Firkowski, Ribeiro andPie, 2015 (Monteiro et al 2018b); B. pitanga Alves, Sawaya, Reis, and Haddad, 2009(Araújo et al 2012, Tandel et al 2014, Goutte et al 2017; B. quiririensis Ribeiro, 2015 (Monteiro et al 2018b); B. sulfuratus Haddad, 2016 (Condez et al 2016); and B. tridactylus Garey, Lima, Hartmann, andHaddad, 2012 (Garey et al 2012).…”

“…The description of the advertisement call of the new species was based on the calls of 17 individuals (Garey et al 2012). Bornschein et al (2018) reported that the note length of B. tridactylus is greater than that of B. albolineatus. To confirm this apparent difference in the duration of notes, the original recordings of B. tridactylus were reanalyzed and compared with our recent recordings of the species.…”