Dear colleagues, On behalf of my co-authors, I am pleased to announce our most recent publication in Marine Mammal Science: MORON, J. R. PAVAN, N. L. STUTS, S. R. REIS, S. S. MAMEDE, N. S. TOLEDO, G. CORSO, G. SOUSA-LIMA, R. S. ANDRIOLO, A. 2018. Whistle variability of Guiana dolphins in South America: Latitudinal variation or acoustic adaptation? Marine Mammal Science, DOI: 10.1111/mms.12572. Abstract A previous comparison of whistles using data sampled at 48 kHz suggested that certain frequency parameters vary along a latitudinal gradient. This geographical pattern may be biased because whistles sampled at higher frequencies could potentially have very different frequency contents. The current study compared the acoustic parameters of Guiana dolphin (Sotalia guianensis) whistles recorded at a higher sampling rate (96 kHz) and from groups occupying two never before sampled sites, Benevente Bay, Espírito Santo, Brazil, and Formosa Bay, Rio Grande do Norte, Brazil, with recordings of other populations in South America. By only considering data sampled at a rate of at least 96 kHz, we aimed to detect differences in whistles across locations. Contrary to previous findings, our analyses do not indicate any clear separation between northern and southern populations based on whistles, and do not corroborate the hypothesis of latitudinal acoustic variation in this species. The variation in Guiana dolphin whistle parameters found here appears to be influenced by latitude to some extent, but several other factors, including sampling method, environmental fluctuations, and social influence on vocal learning, may be confounding the detection of a geographic pattern in these whistle samples. The paper is available online at https://onlinelibrary.wiley.com/doi/10.1111/mms.12572 or you can contact me for a pdf version or for any questions at: julianamoron@hotmail.com<mailto:julianamoron@hotmail.com> Best, ---- Juliana Rodrigues Moron MSc Ecology and Conservation Animal behavior, acoustic communication, cetacean, bioacoustics Collaborating researcher, Laboratório de Bioacústica e Ecologia Comportamental da UFJF -LABEC Associated to Instituto Aqualie + 1 236 464-0544 Lattes<http://buscatextual.cnpq.br/buscatextual/visualizacv.do?id=K4277830D0>