Inferring time-to-speciation from hybrid zone analysis informs assessments of taxonomic inflation

Measuring gene flow across hybrid zones can provide a direct evaluation of reproductive isolation (RI) between evolutionary divergent lineages. Geographic-explicit modelling of gene flow across hybrid zones, known as cline analysis, thus offers a gold standard for species delimitation under the biological species criterion. We here relate divergence time to postzygotic RI as inferred from hybrid zone cline width from studies on amphibians, reptiles, birds, mammals, and insects. The data confirm an overall significant negative correlation between cline width and divergence time (within-clade significant only in amphibians). Out of 108 hybrid zones, hybridizing taxa were younger than 10 million years (Ma) in 104 cases, and younger than 7 Ma in 94 cases, implying that older lineage pairs are usually reproductively isolated. In amphibians, the correlation suggested that shallow and steep hybrid zones, characteristic of subspecies and species, are found with divergence times of <2.6 Ma an..., , , # Data from: Inferring time-to-speciation from hybrid zone analysis informs assessments of taxonomic inflation

[https://doi.org/10.5061/dryad.wwpzgmsv2](https://doi.org/10.5061/dryad.wwpzgmsv2)

## Description of the data and file structure

The dataset was created to relate divergence time to postzygotic RI as inferred from hybrid zone cline width from studies on amphibians, reptiles, birds, mammals, and insects. For this, literature data was screened to collect cline width data, divergence time estimates, and dispersal rates. For amphibians, squamates, mammals, birds, a subgroup of bony fish, lepidopterans, and mollusks, past sets of taxonomically named species were simulated, and their divergence time was calculated using the software TaxoInflationAnalyzer.

### Data Package Structure

All files associated with this dataset are provided within a single compressed archive:

* **Gippner_dataset.zip**

After extraction, the directory structure is as follows:

* Hybrid_zone_data.xlsx
* ..., ,