Priors and Posteriors in Bayesian Timing of Divergence Analyses: The Age of Butterflies Revisited

The origin of taxa presenting a disjunct distribution between Africa and Asia has puzzled biogeographers for more than a century. This biogeographic pattern has been hypothesized to be the result of transoceanic long‐distance dispersal, Oligocene dispersal through forested corridors, Miocene dispersal through the Arabian Peninsula or passive dispersal on the rifting Indian plate. However, it has often been difficult to pinpoint the mechanisms at play. We investigate biotic exchange between the Afrotropics and the Oriental region during the Cenozoic, a period in which geological changes altered landmass connectivity. We use Baorini skippers (Lepidoptera, Hesperiidae) as a model, a widespread clade of butterflies in the Old World tropics with a disjunct distribution between the Afrotropics and the Oriental region. We use anchored phylogenomics to infer a robust evolutionary tree for Baorini skippers and estimate divergence times and ancestral ranges to test biogeographic hypotheses. Our phylogenomic tree recovers strongly supported relationships for Baorini skippers and clarifies the systematics of the tribe. Dating analyses suggest that these butterflies originated in the Oriental region, Greater Sunda Islands, and the Philippines in the early Miocene c. 23 Ma. Baorini skippers dispersed from the Oriental region towards Africa at least five times in the past 20 Ma. These butterflies colonized the Afrotropics primarily through trans‐Arabian geodispersal after the closure of the Tethyan seaway in the mid‐Miocene. Range expansion from the Oriental region towards the African continent probably occurred via the Gomphotherium land bridge through the Arabian Peninsula. Alternative scenarios invoking long‐distance dispersal and vicariance are not supported. The Miocene climate change and biome shift from forested areas to grasslands possibly facilitated geodispersal in this clade of butterflies.

Section: Methodsmentioning

confidence: 70%

“…76 Ma and the split between Hesperiidae and Hedylidae to be c . 106 Ma, and Chazot et al () estimated these nodes to c . 65 Ma and c .…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Out of the Orient: Post‐Tethyan transoceanic and trans‐Arabian routes fostered the spread of Baorini skippers in the Afrotropics

Toussaint

Vila

Yago

et al. 2019

“…Two recent studies estimated the age of Coliadinae at c . 42 and 48 Ma (in Espeland et al ., and Chazot et al ., , respectively). We took two secondary calibration points from the latter which covered most Coliadinae genera.…”

Section: Methodsmentioning

confidence: 88%

Species delimitation and evolutionary relationships among Phoebis New World sulphur butterflies (Lepidoptera, Pieridae, Coliadinae)

Núñez

Genaro

Pérez-Asso

et al. 2019

Self Cite

The most accepted taxonomic treatment of the New World sulphurs of the genus Phoebis Hübner, [1819] recognizes 16 species including those in the current synonyms Aphrissa and Rhabdodryas. This total conflicts with the results of several recent pierid DNA barcode studies across the Neotropics. We used a five‐locus dataset to carry out species delimitation analyses using the coalescence‐based method implemented in bpp software. After testing the resulting species hypotheses using marginal likelihood estimates, we inferred their phylogenetic relationships and performed an ancestral range reconstruction with biogeobears. Our analyses recovered two different hypotheses, 26 and 24 species, that scored the highest marginal likelihood estimate. Differences between these two hypotheses, when reconciled with barcode clusters and morphology, indicated that 24 is the most likely number of species. Phoebis neocypris stat. rev., Phoebis rurina stat. rev., Phoebis virgo stat. rev., Phoebis marcellina stat. rev., Phoebis thalestris stat. rev., and Phoebis rorata stat. rev. are raised to the species rank. We dated the crown age of Phoebis to the mid‐Miocene, with the islands of the Greater Antilles as the most probable ancestral range. Three main clades of Phoebis diverged early in the evolutionary history of the genus, but most extant species‐level diversity arose after the Pliocene–Pleistocene boundary. Our analyses recovered alternate range expansions and contractions, and dispersal from the islands to the continent and back, in the three main clades. Both sympatric and allopatric speciation seem to have shaped the current species richness.

“…We followed a conservative approach by using uniform priors encompassing the 95% highest posterior density (HPD) intervals from Chazot et al . (). The constrained nodes included the divergences of: (i) Brassolini and Morphini to 32–58 Ma; (ii) Melaniti and Dirini to 23–47 Ma; (iii) Lethina, Parargina and Mycalesina to 25–44 Ma; (iv) the crown age of Satyrini to 32–53 Ma; (v) the crown age of the Satyrini's subclade encompassing the tribes Pronophilina, Euptychiina, Satyrina, Erebiina, and other closely related subtribes, to 25–43 Ma; and (vi) the crown age of Satyrinae to 41–67 Ma.…”

Section: Methodsmentioning

confidence: 97%

Species limits in butterflies (Lepidoptera: Nymphalidae): reconciling classical taxonomy with the multispecies coalescent

Matos‐Maraví

Wahlberg

Antonelli

et al. 2019

Self Cite

Species delimitation is at the core of biological sciences. During the last decade, molecular‐based approaches have advanced the field by providing additional sources of evidence to classical, morphology‐based taxonomy. However, taxonomy has not yet fully embraced molecular species delimitation beyond threshold‐based, single‐gene approaches, and taxonomic knowledge is not commonly integrated into multilocus species delimitation models. Here we aim to bridge empirical data (taxonomic and genetic) with recently developed coalescent‐based species delimitation approaches. We use the multispecies coalescent model as implemented in two Bayesian methods (dissect/stacey and bp&p) to infer species hypotheses. In both cases, we account for phylogenetic uncertainty (by not using any guide tree) and taxonomic uncertainty (by measuring the impact of using a priori taxonomic assignments to specimens). We focus on an entire Neotropical tribe of butterflies, the Haeterini (Nymphalidae: Satyrinae). We contrast divergent taxonomic opinion – splitting, lumping and misclassifying species – in the light of different phenotypic classifications proposed to date. Our results provide a solid background for the recognition of 22 species. The synergistic approach presented here overcomes limitations in both traditional taxonomy (e.g. by recognizing cryptic species) and molecular‐based methods (e.g. by recognizing structured populations, and not raising them to species). Our framework provides a step forward towards standardization and increasing reproducibility of species delimitations.