Biogeographic–tectonic calibration of 14 nodes in a butterfly timetree

Abstract

AbstractThe butterfly subtribe Coenonymphina (Nymphalidae: Satyrinae) comprises four main clades found, respectively, in (1) the Solomon Islands, (2) Australasia, (3) NW South America and (4) Laurasia, with a phylogeny: 1 (2 (3 + 4)). In assessing biogeographic evolution in the group we rejected the conversion of fossil‐calibrated clade ages to likely maximum clade ages by the imposition of arbitrary priors. Instead, we used biogeographic–tectonic calibration, with fossil‐calibrated ages accepted as minima. Previous studies have used this approach to date single nodes (phylogenetic–biogeographic breaks) in a group, but we extended the methodology to date multiple nodes. Within the Coenonymphina as a whole, 14 nodes coincide spatially with ten major tectonic events. In addition, the phylogenetic sequence of these nodes conforms to the chronological sequence of the tectonic events, consistent with a vicariance origin of the clades. Dating of the spatially coincident tectonic features provides a timescale for the vicariance events. The tectonic events are: pre‐drift intracontinental rifting between India and Australia (150 Ma); seafloor spreading at the margins of the growing Pacific plate, and between North and South America (140 Ma); magmatism flare‐up along the SW Pacific Whitsunday Volcanic Province–Median Batholith (130 Ma); a change from extension in the Clarence basin, eastern Australia, to uplift of the Great Dividing Range (114 Ma); Pamir Mountains uplift, foreland basin dynamics and high eustatic sea‐levels leading to marine transgression of the proto‐Paratethys Ocean eastward to Central Asia and Xinjiang (100 Ma); predrift rifting and seafloor spreading west of New Caledonia (100–50 Ma); sinistral strike‐slip displacement along the proto‐Alpine fault, New Zealand (100–80 Ma); thrust faulting in the Longmen Shan and foreland basin dynamics around the Sichuan Basin (85 Ma); pre‐drift rifting in the Coral Sea basin (85 Ma); and dextral displacement on the Alpine fault (20 Ma).