Rediscovering Cycloramphus bandeirensis (Anura: Cycloramphidae): natural history and breeding biology of a vulnerable species with a variant reproductive mode

Abstract

Rediscovering Cycloramphus bandeirensis (Anura: Cycloramphidae): natural history and breeding biology of a vulnerable species with a variant reproductive mode. We present here data on the breeding biology of Cycloramphus bandeirensis, including descriptions of the advertisement call and tadpole. Males call from beneath rocks in open grasslands above approximately 2,450 m a.s.l. at the Parque Nacional do Caparaó, southeastern Brazil. Breeding occurs from late October–December, when mist and clouds frequently cover the area. The advertisement call consists of a frst note, followed by two or three shorter ones. The spawn is hidden under rocks from which the males call, and the tadpoles are exotrophic and semiterrestrial. This report of a semiterrestrial tadpole that develops in seclusion in a terrestrial habitat is a variant of Reproductive Mode 19. We compared the ontogeny of the semiterrestrial tadpole of C. bandeirensis to that of generalized tadpoles, and a new function is ascribed to the skin fap that is present in larvae of Cycloramphus. It is suggested that C. bandeirensis be transferred to Vulnerable category (VU, d2) of IUCN; the species has a small geographic range (< 20 km2 ), specialized environmental requirements, is vulnerable, has phylogenetic affnities to species that consistently have undergone local population crashes in southeastern Brazil, and is subject to plausible potential threats in its range (e.g., fres and climate change).

Anurans of the Caparaó National Park and surroundings, southeast Brazil

“…maculiventris) is an abundant species with restricted distribution to altitude lagoons inside the CNP (Lagoa da sombra and Três lagoas) and has explosive reproduction. Cycloramphus bandeirensis can be found in high-altitude habitats at CNP and has a characteristic semiterrestrial reproductive mode (Verdade et al 2019). High-altitude grasslands in the CNP undergo extreme temperature oscillations that could impact local amphibian populations (Veríssimo et al 2012).…”

The tadpole of an insular population of Cycloramphus boraceiensis Heyer, 1983 (Anura: Cycloramphidae) with a review of larval descriptions for species in the genus

“…The descriptions of the tadpoles for different species of Cycloramphus indicate that they are morphologically similar, yet little information about phenotypic and ontogenetic variation is available, making it difficult to use their morphology for species diagnoses (Lima et al, 2010;Nunes-de-Almeida et al, 2016;Verdade et al, 2019). A summary comparing morphological traits for all known larvae is presented in Table 2.…”

“…Based on aspects of their natural history, reproduction, adult and tadpole morphology, Heyer (1983a) grouped these species into five phenetic groups, as follows: C. bolitoglossus, C. eleutherodactylus, C. fuliginosus, C. granulosus and C. ohausi groups. Additionally, using data for natural history (microhabitat of egg laying), reproductive and developmental biology of a few species, the genus has been alternatively arranged into two groups, as suggested by Verdade (2005), and followed in more recent publications (e.g., Lima et al, 2010;Nunes-de-Almeida et al, 2016;Verdade et al, 2019). These two groups were designed to contain the species with exotrophic separated from those with endotrophic tadpoles.…”

“…Species with exotrophic larvae deposit their eggs on the inclined surface of rocks, which are wetted by splashes from waterfalls, small rivers, or by water trickling from soaked soil above the exposed rock. In this group, tadpoles thrive on films of water on the same rock faces where eggs are deposited (Heyer, 1983a;Verdade et al, 2019). The concept of a group of endotrophic larvae was developed based on data gathered for Cycloramphus stejnegeri by Heyer & Crombie (1979).…”

“…Most of the knowledge on larval morphology in the genus was gathered for species with exotrophic tadpoles, perhaps because they are easier to find, usually in the same spots that the adults are found. For the 28 recognized species of Cycloramphus, only ten have tadpoles known and described: C. bandeirensis Heyer (Verdade et al, 2019), C. boraceiensis Heyer (Heyer, 1983a), C. brasiliensis (Steindachner) (Heyer, 1983a), C. fuliginosus Tschudi (Heyer, 1983a), C. izecksohni Heyer (Heyer, 1983a), C. lithomimeticus Da Silva & Ouvernay (Da Silva & Ouvernay, 2012), C. lutzorum Heyer (Lima et al, 2010), C. rhyakonastes Heyer (Nunes-de-Almeida et al, 2016), C. stejnegeri (Noble) (Heyer & Crombie, 1979) and C. valae Heyer (Heyer, 1983b).…”