Multilocus assessment of phylogenetic relationships in Alytes (Anura, Alytidae)

Abstract

With the advent of large multilocus datasets, molecular systematics is experiencing very rapid progress, but important challenges remain regarding data analysis and interpretation. Midwife toads (genus Alytes) exemplify two of the most widespread problems for accurate phylogenetic reconstruction: discerning the causes of discordance between gene trees, and resolving short internodes produced during rapid, successive splitting events. The three species in subgenus Baleaphryne (A. maurus, A. dickhilleni and A. muletensis), the sister group to A. obstetricans, have disjunct and highly restricted geographical ranges, which are thought to result from old vicariant events affecting their common ancestor, but their phylogenetic relationships are still unresolved. In this study we re-address the phylogeny of Alytes with a special focus on the relationships in Baleaphryne with a multilocus dataset including >9000 base pairs of mitochondrial DNA and four nuclear markers (3142bp) in all recognized taxa, including all subspecies of A. obstetricans. Both concatenation and species tree analyses suggest that A. muletensis, endemic to the Balearic island of Mallorca, is the sister taxon to a clade comprising the southeastern Iberian endemic A. dickhilleni and the North African A. maurus. This scenario is consistent with palaeogeological evidence associated with the fragmentation of the Betic-Rifean Massif, followed by the opening of the Strait of Gibraltar. On the other hand, analyses of intraspecific variation in A. obstetricans are inconclusive regarding relationships between major clades and conflict with current subspecific taxonomy.

Multilocus phylogeography of the common midwife toad, Alytes obstetricans (Anura, Alytidae): Contrasting patterns of lineage diversification and genetic structure in the Iberian refugium

“…For ND4 and ß-fibint7 amplification conditions were those described in Gonçalves et al (2007). For PPP3CAint4, RPL9int4 and C-myc amplification conditions followed Maia-Carvalho et al (2014b). Purified products of each reaction were sequenced with the ABI Prism BigDye Terminator v3.1 Sequencing Kit protocol on an ABI3130xl DNA analyzer (Applied Biosystems, Foster City, California, USA).…”

“…Second, Maia-Carvalho et al (2014a) revealed the existence of two well-differentiated groups within A. o. boscai, separated by the Douro River, as suggested by Fonseca et al (2003). Additionally, the recent multilocus assessment of phylogenetic relationships in Alytes by Maia-Carvalho et al (2014b) produced inconclusive results about the relationships between major clades in A. obstetricans and indicated conflict with the current morphology-based subspecific taxonomy.…”

Favourable areas for co‐occurrence of parapatric species: niche conservatism and niche divergence in Iberian tree frogs and midwife toads

“…These local‐scale ecological differences among Hyla and Alytes species were also identified in previous attempts to model their distributions (Arntzen, ) and suggest the existence of niche segregation. The two species pairs have similarly old divergence times (Miocene; see Smith et al ., ; Maia‐Carvalho et al ., ), but the temporal scale of their overlap is markedly different: H. meridionalis is inferred to have entered the Iberian Peninsula in recent times, perhaps even in historical times, via human‐mediated introduction (Recuero et al ., ), whereas A. obstetricans and A. cisternasii have both evolved in situ and coexisted for millions of years (Martínez‐Solano et al ., ; Maia‐Carvalho et al ., ).…”

Dissimilarities in auditory tuning in midwife toads of the genusAlytes(Amphibia: Anura)

“…Alytes obstetricans is a highly diversified taxon, comprising four subspecies, being the sister taxa to A. muletensis , A. maurus , and A. dickhilleni , with the last two species being more closely related (Fig. A) (Maia‐Carvalho et al ., ). This reconstruction suggests that the absence of a strict matching between auditory sensitivity for high frequencies and call dominant frequency is a secondary event in the history of the genus.…”

“…We aimed to determine whether the tuning of the auditory sensitivity of these anurans has a correspondence with the preferences of males and females for calls of low dominant frequencies within the conspecific ranges reported in the literature. In addition, the current knowledge of the phylogenetic relationships among these taxa (Martínez‐Solano et al ., ; Maia‐Carvalho et al ., ) allows interpretations on evolutionary trends of correspondences between auditory sensitivity and vocal traits. These explorations were carried out using a common set‐up between the three taxa, aiming to provide interpretations on potential interspecific differences in auditory sensitivity devoid of difficulties of comparisons based on two previous independent studies (Mohneke & Schneider, ; Bosch & Wilczynski, ).…”