Amphibia-Reptilia (2018) DOI:10.1163/15685381-20181038 Eye malformation baseline in Scinax fuscovarius larvae populations that inhabit agroecosystem ponds in southern Brazil David Sánchez-Domene 1,∗ , Alba Navarro-Lozano 2 , Raphael Acayaba 3 , Katiuce Picheli 2 , Cassiana Montagner 4 , Denise de Cerqueira Rossa-Feres 2 , Fernando Rodrigues da Silva 5 , Eduardo Alves de Almeida 6 Abstract. Events of mass malformations in amphibian populations that have exceeded historical records have been reported over the past thirty years. Many of these events have been linked to human activities that occurred near amphibian breeding habitats. The rise in biofuels has promoted, and continues to promote, the growth of sugarcane plantations in Brazil, with the northwest region of São Paulo State having experienced the largest sugarcane expansion over the past few decades. In this region, we sampled temporary ponds located in agroecosystems dominated to different degrees by sugarcane. We found several larvae of Scinax fuscovarius with eye malformations (anophthalmia, aphakia, microphthalmia and sub-development). In this study, we assessed whether the distance from the ponds to the nearest sugarcane crop, the proportion of sugarcane surrounding the ponds, the presence of pesticides in the ponds, or the proportion of land uses with potential teratogens that surround the ponds were related to the frequencies of amphibian eye malformations. We found pesticides present in 11 of the 18 ponds, but none of the predictor variables was associated with the frequencies of amphibian eye malformations. Thus, our results suggest that the observed frequencies of amphibian eye malformations could be a consequence of natural mutation rates, and these data could be used as a malformation baseline for the region. This malformation baseline is the first reported for amphibians in South America and may be useful in future surveys on amphibian populations in tropical agroecosystems. Keywords: abnormalities, amphibians, pesticides, sugarcane, teratogens. Introduction Malformations are permanent structural defects resulting from morphogenesis errors in organ- isms (Meteyer et al., 2000; Lannoo, 2008). In amphibians, a large range of malformations 1 - Instituto de Pesquisa em Bioenergia, Universidade Es- tadual Paulista, Rio Claro, SP 13500-230, Brazil 2 - Laboratório de Ecologia Teórica, Departmento de Zo- ologia e Botânica, Universidade Estadual Paulista, São José do Rio Preto, SP 15054-000, Brazil 3 - Faculdade de Tecnologia, Universidade de Campinas, Limeira, SP 13484-332, Brazil 4 - Laboratório de Química Ambiental, Departamento de Química Analítica, Instituto de Química, Universidade de Campinas, Campinas, SP 13484-332, Brazil 5 - Laboratório de Ecologia Teórica: Integrando Tempo, Bi- ologia e Espaço (LET.IT.BE), Departmento de Ciências Ambientais, Universidade Federal de São Carlos, Soro- caba, SP 18052-780, Brazil 6 - Departamento de Ciências Naturais, Fundação Uni- versidade Regional de Blumenau, Itoupava Seca, SC 89030-903, Brazil ∗ Corresponding author; e-mail: david.sanchez.domene@gmail.com have been linked to exposure to different ter- atogens emitted into the environment by human activities, such as electromagnetic radiation, chemicals and metals, as well as natural agents, such as viruses and parasites (Ouellet, 2000; Lannoo, 2008). Although mass malformations in amphibians have coincided with global popu- lation declines (Alroy, 2015; Whitfield et al., 2016), the link between malformations and population declines is not strongly supported (Houlahan et al., 2000; Ouellet, 2000; Ankley et al., 2004; Lunde and Johnson, 2012). Indeed, it is not even clear whether the link between prox- imity to human activities and the high occur- rences of malformations in amphibian popula- tions are due to teratogen exposure or to the in- tensive surveillance of freshwater systems over the past decades (Ouellet, 2000). Therefore, un- til further studies clarify the causes and implica- tions of malformations, amphibian populations inhabiting areas susceptible to exposure to po- © Koninklijke Brill NV, Leiden, 2018. DOI:10.1163/15685381-20181038