Phylogeography of Muller's termite frog suggests the vicariant role of the Central Brazilian Plateau

Abstract

Aim To test three different scenarios to account for the geographic distribution of genetic variation in Dermatonotus muelleri, a fossorial frog endemic of the South American diagonal of open formations (DOF) formed by Chaco, Cerrado, and Caatinga biomes: (a) The pan‐DOF hypothesis, where these biomes behave as a single biogeographical unit and DOF species lack population structure; (b) the southwest‐northeast (SW‐NE) hypothesis, where structured populations along the DOF have either asymmetric or unidirectional gene flow in the northeast direction; (c) the vicariance hypothesis, where a pattern of population structure with no or reduced gene flow is observed. Location Caatinga, Cerrado, and Chaco in South America. Methods We sampled 179 individuals across the species distribution and sequenced one mitochondrial and two nuclear markers. We evaluated population structure, the presence, direction, and asymmetry of gene flow, and demographic changes to test three different phylogeographic hypotheses for D. muelleri using a model‐based simulation approach. Results We found two geographically structured lineages with no gene flow, refuting pan‐DOF hypothesis. The Southwest lineage occurs in Chaco and western Cerrado and the Northeast lineage in eastern Cerrado and Caatinga. Our results support the model with demographic change for the Northeast lineage and constant size for Southwest lineage. The vicariance model with divergence time estimated around 4 Ma was preferred. Main conclusions Vicariance was the best explanation for the geographic distribution of genetic variation in Dermatonotus. Divergence time supports the role of Neogene orogeny in central Brazil for the splitting of Dermatonotus lineages. The influence of Pleistocene climatic fluctuations seems restricted to changes in one lineage's population size. Therefore, both ancient and recent events shaped the phylogeography of Dermatonotus. Genetic divergence, lack of gene flow, and the presence of a geographic barrier between lineages indicate the existence of a cryptic, undescribed species in northeastern Brazil.

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“…The geographic break separating these two populations falls in an area of high elevation, which may have isolated the populations. Also, Pleistocene climatic cycles are expected to have influenced the demographic history of at least the Northeast population (Gehara et al, 2017;Oliveira et al, 2018). Oliveira et al (2018) found support for a model of diversification without migration and expansion only for the Northeastern population.…”

“…Here we took a subsample of 88 individuals used in that study. After data assembly population assignment tests (see Supplementary methods) confirmed the existence of two spatially structured clusters (Oliveira et al, 2018) .…”

“…It is an explosive breeder, highly adapted to seasonal environments with pronounced periods of drought (Nomura, Rossa-Feres, & Langeani, 2009). A previous study using three loci (Oliveira et al, 2018) found that D. muelleri is composed by two deeply divergent populations, one distributed in the Caatinga and north of Cerrado, and a second one distributed in the southwest part of Cerrado (Figure 2a). Here we took a subsample of 88 individuals used in that study.…”

Revising the taxonomy ofProceratophrysMiranda‐Ribeiro, 1920 (Anura: Odontophrynidae) from the Brazilian semiarid Caatinga: Morphology, calls and molecules support a single widespread species

“…We also observed that the most common mtDNA haplotype is found all over the species distribution. Geomorphological barriers such as rivers (e.g., Kaefer, Tsuji‐Nishikido, Mota, Farias, & Lima, 2013; Oliveira, Martinez, et al, 2018; Pellegrino et al, 2005) and mountain ranges (e.g., Firkowski, Bornschein, Ribeiro, & Pie, 2016; Oliveira, Gehara, et al, 2018; Shepard & Burbrink, 2008) are usually responsible for patterns of geographic structure in taxa resulting from speciation events. Climatic oscillations or climatic gradients may also act at different latitudes, altitudes, and ecotone zones, directly affecting the genetic structure of some widely distributed species and species pairs (e.g., Boana albopunctata , Prado, Haddad, & Zamudio, 2012; Ameivula ocellifera , Oliveira et al, 2015; Polychrus acutirostris , Fonseca et al, 2018; Lygodactylus klugei , Lanna et al, 2018).…”

Pleistocene expansion and connectivity of mesic forests inside the South American Dry Diagonal supported by the phylogeography of a small lizard*

“…2012a; Oliveira et al. 2018). Our partial Mantel test indicated that altitude resistance is not an important variable in explaining genetic diversity and structure within Colobosaura modesta ; rather, isolation‐by‐distance played a major role in the genetic structure of the species.…”