Subtle environmental variation affects phenotypic differentiation of shallow divergent treefrog lineages in Amazonia

Abstract

Amazonia harbours a vast biotic and ecological diversity, enabling investigation of the effects of microevolutionary processes and environmental variation on species diversification. Integrative approaches combining phenotypic and genetic variation can improve our knowledge on diversification processes in megadiverse regions. Here, we investigate the influence of environmental and geographic variation on the genetic and morphological differentiation in the Amazonian Boana calcarata-fasciata (Anura: Hylidae) species complex. We analysed the variation of one mtDNA gene from individuals of different forest environments, and assessed their phylogenetic relationships and species limits to define the lineages to perform a phenotypic-environmental approach. We collected morphological data (head shape and size) using 3D models and investigated the phylogenetic signal, evolutionary model and influence of environmental variables on morphology. We verified associations between environmental and geographical distances with morphological and genetic variation using distance-based redundancy analyses and Mantel tests. We found an even higher cryptic diversity than already recognized within the species complex. Body size and head shape varied among specimens, but did not present phylogenetic signal, diverging under a selective evolutionary model. Our results show that diverse factors have influenced morphological and genetic variation, but environmental conditions such as vegetation cover, precipitation and climate change velocity influenced morphological diversification. Possible population-level mechanisms such as parallel morphological evolution or plastic responses to similar environments could account for such patterns in these typical Amazonian treefrogs.

Amphibians and reptiles from a protected area in western Brazilian Amazonia (Reserva Extrativista do Baixo Juruá)

“…6B), the two divergent genetic lineages detected at the RBJ are not conspecific with the nominal Boana alfaroi (Caminer & Ron, 2014) or Boana tetete (Caminer & Ron, 2014). In fact, one of the lineages is more closely related to the Boana "clade J" sensu Caminer & Ron (2014) (JN790138, 96%), which corresponds to B. steinbachi Rainha et al, 2021). The other lineage is genetically divergent from any nominal or candidate species and most likely represents an undescribed species (Fig.…”

“…We compared the external morphology (morphometric and meristic characteristics, and coloration patterns) of specimens with original species' descriptions, dichotomous keys, geographically related inventories, and field guides (e.g., Peters & Donoso-Barros, 1986;Dixon et al, 1993;Ávila-Pires, 1995;Gascon, 1996, Lougheed et al, 1999, Gascon et al, 2000Morales, 2002;Peloso & Sturaro, 2008;Moravec et al, 2009;Souza, 2009;Angulo & Icochea, 2010;Maciel & Hoogmoed, 2011;Gordo et al, 2013;Brcko et al, 2013;Fouquet et al, 2014Peloso et al, 2014Peloso et al, , 2016Caminer & Ron, 2014, 2020Caminer et al, 2017;Rivadeneira et al, 2018;Simões et al, 2018;Cunha et al, 2019;Ferrão et al, 2020Ferrão et al, , 2022Sturaro et al, 2020;Magalhães et al, 2020;Rainha et al, 2021;Ribeiro-Júnior et al, 2021), as well as through direct comparisons with other voucher specimens deposited at INPA-H. Evidence for color in life were based on photographs taken during the expeditions of 2005-2007 and 2018. In some cases of the reappraisal of museum specimens, we rely on their external morphology data to determine their updated taxonomic status.…”

“…We consider the possibility of candidate unnamed species when genetic divergence was above 3% (16S), 5% (COI), 23% (Gekkota CYTB), and 10% (ND4), based on thresholds recognized in the literature for these loci and taxonomic groups (Fouquet et al, 2007;Bergmann & Russel, 2007;Kok et al, 2018;Carvalho et al, 2021). Newly generated sequences were deposited on GB under the accession numbers MT472181-MT472182 (Carvalho et al, 2020), MZ018807-MZ018827 (Rainha et al, 2021), MW916091 (Ribeiro-Júnior et al, 2021, and OP296595-OP296615, OP314270-OP314276 and OP277918 (this study).…”

Morphological variation and its correlation with bioclimatic factors in Odorrana graminea sensu stricto

“…The morphological variation among the three clades corresponded with the distribution pattern. The western and eastern clades were in the subtropical region with an average annual temperature of approximately 15°C, while the southern clade was distributed in the tropical region with an average annual temperature of more than 20°C (Qin, 2005;Ding, 2013). The eastern clade was located in Southeast China, in humid and subhumid areas with the longest duration of the summer monsoon and greater precipitation (Qin, 2005;Ding, 2013).…”

“…The eastern clade was located in the south of the middle and lower reaches of the Yangtze River and the Jiangnan Hills of the third step. Affected by the warm and humid air of the Pacific Ocean, this region has a typical subtropical monsoon climate with high humidity and heavy rainfall (Qin, 2005;Ding, 2013). The southern clade evolved to have a smaller body size and larger appendages to adapt to a high temperature, while the eastern clade evolved to have a larger body size and shorter appendages to adapt to a humid climate.…”