Hoplocercine lizards (Enyalioides, Morunasaurus, and Hoplocercus) form a clade of ca. 20 currently recognized species. The phylogenetic relationships among hoplocercine lizards, whose members exhibit striking differences in morphology (e.g., spiny vs. non-spiny tails), have not been clearly resolved by previous molecular phylogenetic studies. We generated a considerably larger dataset including 130 new DNA sequences from one mitochondrial and four nuclear loci for all named and two unnamed species of Hoplocercinae. We analyzed the data under concatenated maximum likelihood (RAxML) and Bayesian (MrBayes) as well as summary coalescent (ASTRAL) approaches. While our phylogenetic hypotheses strongly supported the monophyly of Hoplocercinae, neither Enyalioides nor Morunasaurus was supported as monophyletic. Instead, M. groi was inferred with strong support to form a clade with E. heterolepis and E. laticeps. This clade was in turn the sister taxon to other species of Morunasaurus (M. annularis, M. peruvianus). The remaining species of Enyalioides formed a separate clade with a basal split between western (3 species) and eastern (13 species) subclades. Tree topology tests rejected the monophyly of Enyalioides but failed to reject monophyly of Morunasaurus, suggesting that further study is needed to resolve its taxonomic status. Based on our results, we establish the converted clade names Hoplocercinae, Hoplocercus, Enyalioides, and Morunasaurus, as well as the new clade name Zimiamviasaurus.
Snakes have a wide variety of color patterns that can be related to specific ecological and physiological functions. However, genetic mutations can lead to the appearance of anomalous color patterns, which can directly interfere with the fitness of individuals. Leucism is a chromatic anomaly characterized by the almost total absence of epidermal and dermal chromatophores that produce the color. Corallus hortulana is an arboreal snake with nocturnal habits, widely distributed throughout South America, with a wide range of color patterns, known as polychromatism. Here we report the first case of leucism in Corallus hortulana and discuss the potential ecological implications of this anomaly in this species.
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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