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RELAN - Red de Estudion en Larvas de Anfibios Neotropicales
Knowledge of tadpole morphology and natural history is essential to understand and protect anuran diversity. We provide a regional taxonomic catalog of the tadpoles that occur in the Iron Quadrangle (IQ, Quadrilátero Ferrífero), a hotspot of amphibian diversity and highly threatened region in southeastern Brazil. Using a standardized methodology, free-living larvae of 67 species belonging to 25 genera and 11 families are described and illustrated, including photographs of most species in life, natural history notes, and taxonomic comments. Larvae of seven species and/or candidate species (viz., Fritziana aff. fissilis, Bokermannohyla gr. circumdata, Bokermannohyla aff. nanuzae, Pithecopus aff. rohdei, Scinax aff. machadoi, Scinax aff. perereca, and Scinax rogerioi) are described for the first time and compared to congeners. Most tadpoles of candidate species exhibited remarkable differences in morphology compared to closely related congeners, which could provide diagnostic characters for further formal descriptions. The observed material of many of the previously known tadpoles deviated from published descriptions, which might be useful in future taxonomic studies (e.g., providing characters for the taxonomic delimitation of either small-range species or widespread cryptic species complexes). Illustrated dichotomous and multiaccess identification keys are presented, allowing most species to be readily identified using reliable characters. Considering the high-level threat and huge impacts on IQ’s biodiversity and ecosystem services, particularly from mining, the results presented here provide an important foundation for research and conservation of anuran in this region. Finally, we stress that IQ harbors one of the most ecomorphologically diverse Brazilian tadpole assemblages.
Nyctimantis galeata (Pombal, Menezes, Fontes, Nunes, Rocha & Van Sluys) is a casque-headed frog member of the Lophyohylini tribe (Blotto et al. 2020), narrow-endemic to the municipality of Morro do Chapéu, Bahia state, Brazil (Pombal et al. 2012). This species was initially described as sister of Corythomantis greeningi Boulenger based on shared osteological autapomorphies within Hylidae (see Faivovich et al. 2005; Pombal et al. 2012). However, in the most recent molecular phylogenetic analysis of Lophyohylini, Blotto et al. (2020) redefined the genus Nyctimantis to accommodate species from the former genus Aparasphenodon, Argenteohyla and “Corythomantis galeata” (as initially described; Pombal et al. 2012). Currently, the genus Nyctimantis comprises seven species: N. arapapa (Pimenta, Napoli & Haddad), N. bokermanni (Pombal), N. brunoi (Miranda-Ribeiro), N. galeata, N. pomba (Assis, Santana, Silva, Quintela & Feio), N. rugiceps Boulenger, and N. siemersi (Mertens). Among these, N. arapapa (Lourenço-de-Moraes et al. 2013), N. brunoi (Wogel et al. 2006) and N. siemersi (Céspedez 2000; Cajade et al. 2010) have their tadpoles described, while oral cavity anatomy was only reported for those of N. brunoi and N. siemersi (Wogel et al. 2006; Cajade et al. 2010). Considering that larval morphology generally provides reliable information for anuran systematic and taxonomic studies (Wassersug 1980; McDiarmid & Altig 1999; Haas 2003), a formal comparison of these larvae might highlight additional non-molecular evidence that support them as congeners (Blotto et al. 2020). Herein, we describe the external morphology and oral cavity anatomy of tadpoles of N. galeata and compare it with those of related species.
Physalaemus biligonigerus is a leptodactylid frog that is widely distributed in southern South America and a common member of anuran assemblages that breed in temporary ponds near human settlements. Herein, we analyzed its embryonic and larval morphology through the completion of metamorphosis and constructed a normal table of development. In addition, the timing of development and growth data are provided. Development of P. biligonigerus from fertilization through metamorphosis takes 20–24 days. We recognized 46 discrete developmental stages on the basis of readily discerned, unambiguous, external traits that can be identified in preserved specimens. In contrast with the standard Gosner developmental table, we recognized several particularities in the development of this species. The staging criterion based on external gill morphology presented here is a novel approach to distinguish pre- and post-hatching stages, which could also be employed in other anuran species. We found that anal tube loss in P. biligonigerus occurs earlier than Gosner Stage 41; this trait is highly variable among species and should not be used as a standard criterion. Our analysis demonstrates the value of detailed specific staging tables to characterize anuran life cycles. Furthermore, we point out that the use of generalized standard tables might mask the richness of phenotypic variation during the ontogeny of anuran species.
Bokermannohyla (tribe Cophomantini) is an endemic genus of Brazilian treefrogs containing 32 species arranged into four phenetic groups. The B. pseudopseudis group includes nine species, which are typically found in rupestrian ecosystems of disjunct Brazilian mountain ranges. Tadpoles have been shown to be important sources of information for the taxonomy of this genus, although careful analyses of character variation and descriptions of internal anatomy remain scarce. Since the first description of B. pseudopseudis tadpoles was based on a mixed series containing specimens of B. pseudopseudis and B. sapiranga, we describe the larvae of these two species from their type localities, including their external morphology, oral cavity, and skeletal system. Tadpoles of B. pseudopseudis are easily distinguished from those of B. sapiranga by aspects of their coloration and characters of their oral disc (more labial tooth rows, more numerous submarginal papillae and flaps with labial teeth). These morphological differences may be diagnostic for these two similar species, whereas their chondrocranium, hyobranchial apparatus, and oral cavity are alike, suggesting less variability in these character systems between closely related species. Finally, we provide the first comparison of data on the skeletal system of Bokermannohyla and other Cophomantini, highlighting characters of potential relevance to the systematics of the tribe.
In this work, in-line phase-contrast synchrotron microtomography was used in order to study the external and internal morphology of Thoropa miliaris tadpoles. Whole-specimens of T. miliaris in larval stages of development 28, 37 and 42, collected in the municipality of Mangaratiba (Rio de Janeiro, Brazil) were used for the study. The samples were scanned in microtomography beamline (IMX) at the Brazilian Synchrotron Light Laboratory (LNLS). The phase-contrast technique allowed us to obtain high quality images which made possible the structures segmentation on the rendered volume by the Avizo graphic image editing software. The combination of high quality images and segmentation process provides adequate visualization of different organs and soft (liver, notochord, brain, crystalline, cartilages) and hard (elements of the bone skeleton) tissues.
The Proceratophrys bigibbosa species group comprises four species and is the only group likely to be monophyletic within the genus. I describe the tadpole of P. bigibbosa and its buccopharyngeal morphology. Comparisons among Proceratophrys larvae in the light of a phylogenetic tree suggest that a conical vent tube, tail fin originating in the body/tail junction, large A2 gap, and trapezoid median ridge may represent putative synapomorphies for the P. bigibbosa group. © 2018 by the American Society of Ichthyologists and Herpetologists.
The Odontophrynus americanus species group is a complex of diploid and tetraploid species hardly distinguished by morphological characters. It currently consists of three allopatric diploid species (i.e. O. cordobae, O. lavillai, and O. maisuma) and one widely distributed tetraploid species (i.e. O. americanus). We herein describe a new diploid allopatric species from campo rupestre, a typical phytophysiognomy of the Espinhaço Range, Brazil. The new species is distinguishable by the diploid complement of 2n = 2x = 22 chromosomes, small to medium-sized dorsal dark brown blotches with low contrast on a light brown background, light mid-dorsal stripe absent or greatly interrupted in most specimens with yellowish coloration as the background of both head and flanks of the body, advertisement call with dominant frequency of 840–1080 Hz, pulse rate of 90.5–106.7 pulses/s, and small tadpoles (TL = 24.30–35.69 mm).