The remarkable larval morphology of Rhaebo nasicus (Werner, 1903) (Amphibia: Anura: Bufonidae) with the erection of a new bufonid genus and insights into the evolution of suctorial tadpoles.

Tadpoles serve as crucial evidence for testing systematic and taxonomic hypotheses. Suctorial tadpoles collected in Guyana were initially assigned to Rhaebo nasicus through molecular phylogeny. Subsequent analysis of larval and adult morphological traits revealed synapomorphies within the clade encompassing R. nasicus and R. ceratophrys, prompting the recognition of a new genus described herein as Adhaerobufo. The new genus is distinguished from other bufonids by specific phenotypic traits including an enlarged, suctorial oral disc with distinct papillae arrangements, and the presence of certain muscles and narial vacuities at the larval stage. However, only a few adult external characteristics (e.g., enlarged eyelids, infraocular cream spot), seem to be reliably discriminative from related genera. This study underscores the significance of larval morphology in anuran systematics and offers new insights into the evolution of suctorial and gastromyzophorous larvae within bufonids.

Gastrotheca Fitzinger, 1843 tadpole morphology: Larval cranium description and its evolutionary implications (Amphibia: Anura: Hemiphractidae).

Hemiphractids have a singular mode of reproduction that involves maternal care. The Andean-endemic Gastrotheca marsupiata species group includes direct-developing and tadpole-bearing species, the latter trait being unique among Gastrotheca. Larval morphology has proven to be a valuable source of evidence to understand the taxonomy and evolution of frogs but remains understudied in Hemiphractids. Herein, we redescribe the larval cranium of G. espeletia, G. gracilis, G. marsupiata, G. peruana, G. pseustes, and G. riobambae, and describe those of G. aureomaculata, G. chrysosticta, G. litonedis, G. monticola and G. psychrophila. Additionally, based on the data gathered, we explore their phylogenetic significance, expanding the knowledge regarding Gastrotheca larval internal morphology. We suggest that the presence of the posterolateral process of crista parotica, the concave palatoquadrate, the quadratoorbital commissure, and the proximal commissures II and III are putative synapomorphies for Gastrotheca. Furthermore, we suggest the long pseudopterygoid process as a putative synapomorphy for Hemiphractyidae.

First description of buccopharyngeal anatomy in Pelodryadinae larvae: Morphological comparison and systematic implications (Anura: Hylidae: Pelodryadinae: Litoria rubella and Ranoidea caerulea).

Pelodryadinae, the Australian tree frogs, is a monophyletic group endemic to the Australo-Papuan region. Although we have a relatively good knowledge about tadpoles' phenotypic diversity in terms of external morphology, information about internal anatomy is rare for the subfamily; for instance, their buccopharyngeal cavity is completely unknown. Herein I describe for the first time the buccopharyngeal anatomy of two pelodryadins: Litoria rubella and Ranoidea caerulea. I compare my results with available evidence from Phyllomedusidae, that is, the sister clade to Pelodryadinae, and briefly comment on buccopharyngeal cavity within Hylidae. Both species can be readily distinguished based on lateral ridge, postnarial, buccal roof arena, infralabial papillae, and lingual papillae. Variation between the two species may suggest a large diversity within Pelodryadinae. Pelodryadinae and Phyllomedusinae present similar buccopharyngeal morphologies, although Agalychnis callidryas has a unique morphology and putative apomorphic transformations can be observed in Pithecopus + Phyllomedusa, Ranoidea, and Phasmahyla.

Buccopharyngeal morphology of the tadpoles of Scinax v-signatus/, with comments on larval characters of the S. perpusillus/ species group (Amphibia: Anura: Hylidae).

The Neotropical genus Scinax Wagler currently comprises 127 species of small treefrogs distributed from southern Mexico to Argentina and Uruguay, including some islands such as Trinidad and Tobago, and St. Lucia (Frost 2020). Two major clades are recognized within Scinax, the S. catharinae and the S. ruber clades. The former is composed of two species groups, the S. catharinae and the S. perpusillus groups (Faivovich 2002; Faivovich et al. 2005). The S. perpusillus species group currently comprises 13 species: S. alcatraz (Lutz); S. arduous Peixoto; S. atratus (Peixoto); S. belloni Faivovich, Gasparini Haddad; S. cosenzai Lacerda, Peixoto Feio; S. faivovichi Brasileiro, Oyamaguchi Haddad; S. insperatus Silva Alves-Silva; S. littoreus (Peixoto); S. melloi (Peixoto), S. peixotoi Brasileiro, Haddad, Sawaya Martins; S. perpusillus (Lutz Lutz); S. tupinamba Silva Alves-Silva; and S. v-signatus (Lutz). These species are endemic of the Brazilian Atlantic Forest and are recognized by their intimate association with bromeliads (Fig. 1), in which adults breed and lay their eggs, and tadpoles develop (Peixoto 1987, 1995; Alves-Silva Silva 2009).

Concentrated evolutionary novelties in the foot musculature of Odontophrynidae (Anura: Neobatrachia), with comments on adaptations for burrowing.

We studied the foot musculature of the fossorial family Odontophrynidae (composed of the genera Macrogenioglottus, Odontophrynus, and Proceratophrys) plus several outgroup taxa from Hyloidea and other burrowing taxa from across Anura. We found novel character-states supporting the monophyly of Odontophrynus, Proceratophrys, and Odontophrynus + Macrogenioglottus. The character-states observed in O. cultripes support conflicting phylogenetic positions within Odontophrynus. A comparison of some novel character-states with a diverse sample of burrowing taxa suggests that some modifications of the foot musculature might be involved in digging.

Two new species of Proceratophrys Miranda-Ribeiro, 1920 (Anura; Odontophrynidae) from the Atlantic forest, with taxonomic remarks on the genus.

We describe two new species of Proceratophrys allied to the P. appendiculata species complex by the presence of single and long palpebral appendages and a triangular rostral appendage. Proceratophrys izecksohni sp. nov. is characterized by having small to medium size (SVL 32.1-54.2 mm in males), elongated hindlimbs (thigh length plus tibia length corresponding to more than 90% of snout-vent length), a broad head (head width corresponding to 55% of the snout-vent length), and by the light brown gular region and a cream colored ventral surface with scattered brown dots. Proceratophrys belzebul sp. nov. is characterized by its medium size (SVL 40.5-51.3 mm in males), by the absence of contact between the nasals bones and between the nasals and frontoparietals, by a very reduced iliac projection, by having frontoparietal bones very depressed and broad rostrally, by the smooth surface of the squamosal and nasal, by shallow, inconspicuous ventral pits on the maxillae, and by the females presenting the gular region dark brown. The two new species were previously confused with P. appendiculata for which we provide a new diagnosis. A molecular analysis based on mitochondrial and nuclear genes recovers a monophyletic Proceratophrys with high support, and the two new species in a clade with P. appendiculata and P. tupinamba. The data also reinforce the idea that the species groups presently admitted to the genus are not monophyletic.

Larval chondrocranium morphology of five species of Proceratophrys Miranda-Ribeiro (Amphibia; Anura; Odontophrynidae).

The chondrocranium and hyobranchial morphology are described for the tadpoles of five species of Proceratophrys Miranda-Ribeiro. The chondrocranium of P. appendiculata, P boiei, P laticeps and P. tupinamba are very similar and can be distinguished from that of P. cristiceps by: 1) less developed processus muscularis; 2) thinner palatoquadrate; 3) broadest ethmoidal region; 4) longer cornua trabeculae; and 5) morphology f the suprarostral cartilages. A morphological variation among Proceratophrys boiei is described. It reveals the existence of at least three distinct evolutionary lineages under this name. A brief comparison with other cycloramphid species is also provided.