Marco Rada

Anurans of the family Centrolenidae are a highly diverse clade of Neotropical treefrogs. In the last two decades, glassfrogs have become a model system for studies in ecology and evolutionary biology, in part because their taxonomy and phylogenetic relationships are considered relatively well established. However, there are still many gaps in our knowledge, for example, which morphological characters are important for species delimitation. Consequently, several species complexes in Centrolenidae remain unresolved. Using data on external and internal morphology of adult individuals, tadpoles, advertisement call traits and genetic sequences, we describe a new species of glassfrog (Nymphargus pijao sp. nov.) endemic to Colombia that has been previously missasigned to Nymphargus griffithsi. We include in this description data of three phenotypic characters related to pectoral musculature and testis size, which have been traditionally overlooked in studies about the taxonomy and systematics of glassfrogs. In addition, we present details of a low-cost method implemented in the field to rear tadpoles of the new species. This methodology can solve common problems during the management and care of glassfrogs egg masses and tadpoles, and hence, promotes their description for more species and a better knowledge of the anuran biodiversity in Neotropics.

In anurans, vocalisations are the main behavioural modality of communication. Hence, the description of acoustic signals in anurans is important for understanding many aspects of their biology. We describe for the first time the advertisement calls for eight glass frog species (Centrolene antioquiensis, ”Centrolene” robledoi, Nymphargus caucanus, N. chami, N. ignotus, N. rosada, N. spilotus, Sachatamia orejuela) and provide additional data on the recently described advertisement calls of Espadarana audax. In addition, we review the current knowledge of advertisement calls for all glass frog species (Centrolenidae). Based on the predominant temporal and the spectral structure, we identified three major types of calls in the family: 1) calls consisting of unpulsed short notes with amplitude modulation, similar to a ‘Tic’, 2) calls consisting of one long note (whistled) without amplitude modulation, similar to a ‘Tii’ and 3) calls consisting of pulsed or pulsatile notes, similar to a ‘Trii’. We mapped these acoustic characters in the context of the evolutionary history of Centrolenidae. Descriptions presented here offer evidence to recognise most centrolenid calls using measurable characters in the field or laboratory. As such, we hope to stimulate future studies based on bioacoustical analysis in this widespread and highly diverse Neotropical clade.

True toads of the genus Rhinella are among the most common and diverse group of Neotropical anurans. These toads are widely distributed throughout South America, inhabiting a great diversity of environments and ecoregions. Currently, however, the genus is defined solely on the basis of molecular characters, and it lacks a proper diagnosis. Although some phenetic species groups have traditionally been recognized within Rhinella, the monophyly of some of them have been rejected in previous phylogenetic analyses, and many species remain unassigned to these poorly defined groups. Additionally, the identity and taxonomy of several species are problematic and hinder the specific recognition and description of undescribed taxa. In this work, we first perform phylogenetic analyses of separate mitochondrial and nuclear datasets to test the possible occurrence of hybridization and/or genetic introgression in the genus. The comparative analysis of both datasets revealed unidirectional mitochondrial introgressions of an unknown parental species into R. horribilis (“ghost introgression”) and of R. dorbignyi into R. bernardoi; therefore, the mitochondrial and nuclear datasets of these species were considered separately in subsequent analyses. We performed total-evidence phylogenetic analyses that included revised molecular (four mitochondrial and five nuclear genes) and phenotypic (90 characters) datasets for 83 nominal species of Rhinella, plus several undescribed and problematic species and multiple outgroups. Results demonstrate that Rhinella was nonmonophyletic due to the position of R. ceratophrys, which was recovered as the sister taxon of Rhaebo nasicus with strong support. Among our outgroups, the strongly supported Anaxyrus + Incilius is the sister clade of all other species of Rhinella. Once R. ceratophrys is excluded, the genus Rhinella is monophyletic, well supported, and composed of two major clades. One of these is moderately supported and includes species of the former R. spinulosa Group (including R. gallardoi); the monophyletic R. granulosa, R. crucifer, and R. marina Groups; and a clade composed of the mitochondrial sequences of R. horribilis. The other major clade is strongly supported and composed of all the species from the non-monophyletic R. veraguensis and R. margaritifera Groups, the former R. acrolopha Group, and R. sternosignata. Consistent with these results, we define eight species groups of Rhinella that are mostly diagnosed by phenotypic synapomorphies in addition to a combination of morphological character states. Rhinella sternosignata is the only species that remains unassigned to any group. We also synonymize nine species, treat three former subspecies as full species, and suggest that 15 lineages represent putative undescribed species. Lastly, we discuss the apparently frequent occurrence of hybridization, deep mitochondrial divergence, and “ghost introgression”; the incomplete phenotypic evidence (including putative character systems that could be used for future phylogenetic analyses); and the validity of the known fossil record of Rhinella as a source of calibration points for divergence dating analyses.

The interaction between homing and parental care offers insights about the motivational aspects underlying movement patterns in animals. For species that care for offspring at fixed locations, offspring mortality in the absence of care might impact a parent’s motivation to home after being displaced from young. We tested whether homing motivation is related to parental care in the glassfrog Centrolene savagei (Centrolenidae), a species with extended male care and territoriality. Specifically, we evaluated how parental status (i.e. caring for eggs vs unmated yet territorial males) and translocation distance impacts homing motivation. Along a stream located in the Central Andes of Colombia, we translocated 23 male C. savagei between 5 and 80 m away from their reproductive territories. We found that both parental status and translocation distance impacts homing motivation, as caring males were more likely to return to their initial territories after translocation. Seven of the 16 caring males and one of the seven unmated males returned to the initial capture site. While unmated males might be motivated to home if reproductive territories are a limited resource, our results support that caring males exhibited much higher motivation to home. It is possible that the fitness benefits accrued from caring for vulnerable offspring alters the cost-to-benefits of homing, and thus accounts for a greater frequency of homing among caring males. This study contributes to understanding how aspects of life history (e.g. parental care) relate to homing motivation in vertebrates.

The relationships of the hyline tribe Dendropsophini remain poorly studied, with most published analyses dealing with few of the species groups ofDendropsophus. In order to test the monophyly of Dendropsophini, its genera, and the species groups currently recognized inDendropsophus, 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 ofXenohyla, and 93 of the 108 recognized species ofDendropsophus. The phenomic dataset includes 46 terminals, one per species (34Dendropsophus, oneXenohyla, and 11 outgroup species). Our results corroborate the monophyly of Dendropsophini and the reciprocal monophyly ofDendropsophusandXenohyla. Some species groups ofDendropsophusare paraphyletic (theD. microcephalus,D. minimus, andD. parvicepsgroups, and theD. rubicundulusclade). On the basis of our results, we recognize nine species groups; for three of them (D. leucophyllatus,D. microcephalus, andD. parvicepsgroups) 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 ofDendropsophus.

Ikakogi is a behaviorally and morphologically intriguing genus of glassfrog. Using tadpole morphology, vocalizations, and DNA, a new species is described from the Sierra Nevada de Santa Marta (SNSM), an isolated mountain range in northern Colombia. The new taxon is the second known species of the genus Ikakogi and is morphologically identical to I. tayrona (except for some larval characters) but differs by its genetic distance (14.8% in mitochondrial encoded cytochrome b MT-CYB; ca. 371 bp) and by the dominant frequency of its advertisement call (2928–3273 Hz in contrast to 2650–2870 Hz in I. tayrona). They also differ in the number of lateral buccal floor papillae, and the position of the buccal roof arena papillae. Additionally, the new species is differentiated from all other species of Centrolenidae by the following traits: tympanum visible, vomerine teeth absent, humeral spines present in adult males, bones in life white with pale green in epiphyses, minute punctuations present on green skin dorsum, and flanks with lateral row of small, enameled dots that extend from below eye to just posterior to arm insertion. We describe the external and internal larval morphology of the new species and we redescribe the larval morphology of Ikakogi tayrona on the basis of field collected specimens representing several stages of development from early to late metamorphosis. We discuss the relevance of larval morphology for the taxonomy and systematics of Ikakogi and other centrolenid genera. Finally, we document intraspecific larval variation in meristic characters and ontogenetic changes in eye size, coloration, and labial tooth-rows formulas, and compare tadpoles of related species. Ikakogi tayrona has been proposed as the sister taxon of all other Centrolenidae; our observations and new species description offers insights about the ancestral character-states of adults, egg clutches, and larval features in this lineage of frogs.

Thirty species of the glassfrogs genus Nymphargus, including a new species, are known to inhabit the cloud forest of the Andes of Colombia and Ecuador. Four of these species (Nymphargus anomalus, N. ignotus, N. rosada, and the new species) are unusual by having a tan-brown dorsal coloration instead of the widespread green coloration commonly found in glassfrogs. Herein, we review tan-brown glassfrogs species, providing information on their external morphology, color ontogeny, ecology, and distribution. The new taxon inhabits the Andes of southwestern Colombia, Departamento del Cauca, and it is distinguished from other centrolenids by having a tan-brown dorsum with dark spots lacking ocelli, reduced (basal) webbing between outermost fingers, and lacking iridophores on the digestive tract and hepatic peritonea. We also find that Nymphargus ignotus is a polymorphic species distributed along the western flank of the Cordillera Occidental in Colombia. The egg masses of N. ignotus are similar to those...