The Stream Tadpoles ofRhinella rumbolli(Anura: Bufonidae)

Abstract

The Rhinella veraguensis group is likely a paraphyletic assemblage that contains 16 species of Andean toads. To date, descriptions are available for larval stages of only three species, all of which possess a distinct sucker in the abdominal region. In this study, we describe the tadpoles of Rhinella rumbolli, a medium-sized Salta Toad typical of forest streams in northwestern Argentina. Thirty-three larvae (Gosner Stages 32-36) were processed for studies of the external morphology, buccal cavity, and musculoskeletal system. These larvae show a mosaic of features, some typical of the genus and some others unique to the R. veraguensis group. Several character states are specific to R. rumbolli, namely the lack of an abdominal sucker, 2-4 lingual papillae, and the absence of adrostral cartilages. Some traits are frequent in other stream tadpoles such as the muscular tail, large oral disc with complete labial rows, and the wide and robust anterior neurocranium. Bufonid tadpoles exhibit an extraordinary variation in ecology, such as preferred microhabitat, and the diversity within the family is exemplified within the genus Rhinella. Further comparative morphological and developmental studies, framed in the context of phylogenetic hypotheses, are needed in order to explore the pattern variation in different clades and to discuss character evolution and form-function relationships.

Comparative morphology of pond, stream and phytotelm-dwelling tadpoles of the South American Redbelly Toads (Anura: Bufonidae:Melanophryniscus)

“…This process is not evident or low and in other bufonids (e.g. Fabrezi & Vera, ; Larson, ; Kolenc et al ., ) and wide and square in Rhinella quechua and R. rumbolli (Aguayo et al ., ; Haad, Vera Candioti & Baldo, in press). The presence of the quadrato‐orbital commissure joining the muscular process and the neurocranium was proposed as a synapomorphy of the clade joining all bufonids but Melanophryniscus [character in Frost et al .…”

“…Interestingly, not all aspects of variation patterns are the same when compared to lentic and lotic tadpoles of the bufonid Rhinella . Whereas stream species of this genus have short articular processes and ascending processes attached in an acute angle, just like in lotic Melanophryniscus , trabecular horns are instead, longer in pond Rhinella species (Haad, et al ., in press). The neurocranium of phytotelm tadpoles is the most different, with short trabecular horns, unusually large otic capsules, and an ascending process almost perpendicular to the axis of the neurocranium.…”

The remarkable larval anatomy of Proceratophrys minuta Napoli, Cruz, Abreu and Del‐Grande, 2011 (Amphibia: Anura: Odontophrynidae)

“…Cartilago Meckeli-lower lip; and/or oral sucker Absent Aguayo, Lavilla, Vera Candioti, & Camacho, 2009;Baldo et al, 2014;Carr & Altig, 1991;Haas, 2001Haas, , 2003Haad, Vera Candioti, & Baldo, 2014;Kolenc et al, 2013;Vera Candioti, 2007 Calyptocephalellidae ---…”

Sequence of chondrocranial development in the oriental fire bellied toad Bombina orientalis

“…Investigating the sequential development of cartilaginous elements in a variety of vertebrate species is essential for an understanding of evolutionary changes and for the identification of ontogenetic novelties as well as heterochronic events. The morphology of the chondrocranium of anuran tadpoles has been described in several species (e.g., Candioti, 2007; Candioti, Haas, Altig, & Peixoto, 2017; Haad, Candioti, & Baldo, 2014; Kolenc et al, 2013). Unfortunately, sequential descriptions of cartilage formation from the onset of chondrification until the premetamorphic stage in anurans are scarce (Lukas & Olsson, 2018a; Reiss, 1997) or outdated (Gaupp, 1906; Parker, 1876, 1879; Stephenson, 1951; Stöhr, 1882; van der Westhuizen, 1961).…”