Records of malformation in amphibians have significantly increased on a global scale. The main causes of malformations are linked to environmental contaminants, and records in preserved environments are uncommon. We reported malformations in three anuran species belonging to three families: Crossodactylustimbuhy (Hylodidae), Proceratophrysschirchi (Odontophrynidae) and Thoropamiliaris (Cycloramphidae). All records were found within the Reserva Biológica Augusto Ruschi, a well-preserved protected remnant of Atlantic rainforest located in the mountains of the state of Espírito Santo, southeastern Brazil. The malformations detected were hemimelia (long bone shortened) with ectrodactyly (digit absent) and brachydactyly (digit shortened) in C.timbuhy, microphtalmia (small eye) in P.schirchi and ectrodactyly in T.miliaris. Further studies are recommended to enable a better understanding about the incidence and causes of malformations within preserved areas.
Ameerega trivittata is a widely distributed dendrobatid species with colour polymorphism for which only the diploid number, nucleolar organizer regions (NORs) and heterochromatic pattern are known. Here, we investigated the existence of cytogenetic structure in A. trivittata populations with different morphotypes. Four morphotypes and their geographical distributions were defined. All the individuals have 24 chromosomes and a similar heterochromatic pattern, the same location of telomeric regions and 5S rDNA. The NOR site was coincident with the 18S rDNA in pair 9, but some individuals presented an additional site in one of the homologues of pair 11. The highest variation was found in the microsatellite distribution patterns. Comparing the cytogenetic characters of the individuals, two groups were detected: (1) Tabatinga (morphotype B) and Benjamin Constant (morphotype A), and (2) Presidente Figueiredo and Tefé (morphotype C). The cytogenetic data appear to be correlated to the structure pattern of the morphotypes, and corroborate the dispersal routes proposed in the literature. This is the first study of population cytogenetics for the group. Our results provide a series of cytogenetic characters for A. trivittata and for Dendrobatidae for the first time and highlight the importance of considering cytogenetics in population research.
Discussions about auditory systems and sound dynamics in snakes are frequent. The known frequency of sounds produced by snakes ranges from 0.2 - 7.5 KHz, ranging from imperceptible sounds to humans to audible and observable squeaks. The hiss and whistles are the most common sound and are not considered vocalizations. During a nocturnal survey on June 13, 2021, in the northern Brazilian Amazon, we observed the first record of vocalization in a South American snake. Emitted by the individual from Dipsas catesbyi has a duration of 0.06 seconds, reaching 3036 Hz in its peak frequency, with an amplitude of 2761 to 4152 Hz of frequency in its main emission. Vocalizations were made during the exhalation of air through the larynx. The modulation differs from all patterns observed for snakes resembling the agonistic call of anuran amphibians, which could characterize an evolutionary mimicry of this behavior. Vocal emission via the larynx can generate internal vibrations perceptible to the auditory system of snakes, which, when vocalizing, vibrate the laryngeal cartilage and vocal cord. Our hypothesis is that structured vocal emission through laryngeal air exhalation may be a characteristic shared by other species of the Colubridae family.
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