Editorial Type:
Article Category: Research Article
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Online Publication Date: 27 Jul 2021

The Tadpoles and Advertisement Call of Trachycephalus imitatrix and T. dibernardoi (Anura: Hylidae)

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Page Range: 237 – 252
DOI: 10.1670/20-010
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ABSTRACT

Herein, we describe the external larval morphology, internal oral features, and chondrocranium of Trachycephalus imitatrix and Trachycephalus dibernardoi and the advertisement call of T. imitatrix. To our knowledge, this is the first thorough description of the larval chondrocranium for the genus Trachycephalus. The tadpole of T. imitatrix is overall similar to the other congeneric species, but can be distinguished from them by the following combination of characteristics: presence of two folds in the posterior labium, clumped submarginal papillae, tail ending in a flagellum, buccal roof arena lacking papillae, and seven postnarial papillae. The tadpole of T. dibernardoi can be distinguished from its congeners by the following combination of characteristics: snout rounded in lateral view, absence of interruption in teeth rows, uniseriate and alternated row of marginal papillae, two pairs of infralabial papillae, and absence of projection of the dorsal velum. The advertisement call of T. imitatrix is very similar to that of Trachycephalus nigromaculatus, but can be distinguished from it by its lower dominant frequency. Additionally, both spectral and temporal features of the call can distinguish T. imitatrix from other congeneric species. Our results help understand the differentiation of larval and acoustical characteristics within the genus Trachycephalus.

RESUMO

Aqui, descrevemos a morfologia larval externa, características orais internas e condrocrânio de Trachycephalus imitatrix e T. dibernardoi e o canto de anúncio de T. imitatrix. Até onde sabemos, esta é a primeira descrição completa do condrocrânio de uma larva do gênero Trachycephalus. O girino de T. imitatrix é semelhante às outras espécies congenéricas, mas pode ser diferenciado delas pela seguinte combinação de características: presença de duas dobras no lábio inferior, papilas submarginais agrupadas, cauda terminando em flagelo, arena bucal sem papilas e sete papilas pós-narinas. O girino de T. dibernardoi pode ser diferenciado de seus congêneres pela seguinte combinação de características: focinho arredondado em vista lateral, ausência de interrupção nas fileiras de dentículos, papilas marginais uniseriadas e alternadas, dois pares de papilas infralabiais, ausência de projeção do velum dorsal. O canto de anúncio de T. imitatrix é muito semelhante ao de T. nigromaculatus, mas distingue-se por sua menor frequência dominante. Além disso, as características espectrais e temporais do canto podem distinguir T. imitatrix de outras espécies congenéricas. Nossos resultados ajudam a entender a diferenciação das características larvais e acústicas dentro do gênero Trachycephalus.

Copyright: Copyright 2021 Society for the Study of Amphibians and Reptiles 2021
Fig. 1.
Fig. 1.

External morphology of the tadpole of Trachycephalus imitatrix (DZSJRP 2460.1) at stage 37 from Piquete, São Paulo, Brazil. (A) Lateral view; (B) dorsal view; (C) oral apparatus. Scale bar = 1 cm.

Fig. 2.
Fig. 2.

External morphology of the tadpole of Trachycephalus dibernardoi (DZSJRP 1829.1) at stage 37. (A) Lateral view; (B) dorsal view, and (C) oral apparatus. Scale bar = 1 cm.

Fig. 3.
Fig. 3.

Internal oral features of the tadpole of Trachycephalus imitatrix (DZSJRP 2460.1) at stage 37, collected at Piquete, São Paulo, Brazil. (A) Buccal floor; (B) buccal roof. Scale bar = 1 mm (A) and 30 μm (B). BFA = buccal floor arena, BRA = buccal roof arena, CH = choanae, DV = dorsal velum, GLT = glottis, IP = infralabial papillae, LP = lingual papillae, LPMR = lateral ridge papillae, MR = median ridge, PBFA = papillae of buccal floor arena, PPNA = post narial papillae, PNP = prenarial papillae, VV = ventral velum.

Fig. 4.
Fig. 4.

Internal oral features of the tadpole of Trachycephalus dibernardoi (DZSJRP 1829.1) at state 37. (A) Buccal floor; (B) lingual region; (C) buccal roof; (D) prenasal and postnasal arena. BFA = buccal floor arena, BRA = buccal roof arena, CH = choanae, DV = dorsal velum, GLT = glottis, IP = infralabial papillae, LP = lingual papillae, LPMR = lateral ridge papillae, MR = median ridge, PBFA = papillae of buccal floor arena, PPNA = post narial papillae, PNP = prenarial papillae, VV = ventral velum.

Fig. 5.
Fig. 5.

Neurocranium and hyobranchial apparatus of the tadpole of Trachycephalus imitatrix (DZSJRP 2460.1) at stage 38. (A) Suprarostral cartilage; (B) dorsal view; (C) ventral view; (D) lateral view; (E) hyobranchial apparatus. Legends in A: pa, pars alaris; pc, pars corporis. Legends in B, C, and D: as, arcus subocularis; cc, cavum cranii; cli, cartilago labialis inferior; cls, cartilago labialis superior; cm, cartilago Meckeli; ca, cartilago orbitalis; ct, cornua trabeculae; fc, foramen craneopalatinum; fcp, foramen caroticum primarium; fpo, fissura prootica; fo, foramen opticum; oc, otic capsule; pa, processus ascendens; pao, processus antorbitalis; paq, processus articularis quadrati; pm, processus muscularis quadrati; pra, processus retroarticularis; sf, fenestra subocularis; tn, tectum nasi; tp, tectum parietale. Legends in E: ca, condylus articularis; cb, ceratobranchiales; cp+cu, copula posterior and processus urobranchialis; pal, processus anterolateralis hyalis; h, hypobranchiales; pa, processus anterior hyalis; pab, processus anterior branchialis; pal, processus anterolateralis hyalis; pp, processus posterior dorsalis; pr, pars reunens; s, spiculae; tc, commissura terminalis.

Fig. 6.
Fig. 6.

Neurocranium and hyobranchial apparatus of the tadpole of Trachycephalus dibernardoi (DZSJRP 1829.1) at stage 38. (A) Dorsal view; (B) ventral view; (C) lateral view. For legends, see Fig. 5.

Fig. 7.
Fig. 7.

Phylomorphospace showing the distribution of the species in the reduced shape space composed by the first two principal components of a phyloPCA, along with the phylogeny from Blotto et al. (2020) superimposed. The images of tadpoles represent shape associated with extreme values of each principal component: negative PC1 = T. dibernardoi, positive PC1 = T. coriaceus; negative PC2 = T. mesophaeus, positive PC1 = T. typhonius. Images are not to scale, as we used size-corrected measurements to run the phyloPCA.

Fig. 8.
Fig. 8.

Results of the DAPC, showing the significant difference in the morphology of the tadpoles of T. imitatrix and T. dibernardoi. (A) Density of individuals along the first discriminant function; (B) plot showing the probability of assignment of individuals to the prior groups (species); (C) loadings of the variables that most contributed to the separation of the two species along the DF1; (D) ordination diagram showing the distribution of the samples of the two species.

Fig. 9.
Fig. 9.

Ordination diagram showing the results of Principal Components Analysis made with the linear morphometric data showing the distribution of the tadpoles of T. imitatrix and T. dibernardoi.

Fig. 10.
Fig. 10.

Oscillogram (A) and audiospectrogram (B) of the advertisement call of T. imitatrix (DZSJRP 12123) recorded at the Serra da Bocaina National Park, São José do Barreiro, São Paulo, Brazil. Air temperature: 15.5°C. File analyzed is available at Fonoteca Neotropical Jacques Vielliard (FNJV 0037787).

Contributor Notes

2 Corresponding Author. E-mail: diogo.provete@ufms.br
Accepted: 10 Mar 2021
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