Guilin Hu, Baozhen Hua. Historical Biogeography of the Short-faced Scorpionflies (Insecta: Mecoptera:Panorpodidae)

Historical Biogeography of the Short-faced Scorpionflies (Insecta: Mecoptera:Panorpodidae)

Guilin Hu, Baozhen Hua.

Journal of Biogeography

DOI: 10.1111/jbi.12778

Abstract:

Aim: Panorpodidae is a species-poor family of Mecoptera, containing only 13species in its two genera, Panorpodes and Brachypanorpa. They are found disjunctly in eastern Asia and North America, and this distribution has been deeply affected by the region’s complex geological and climatic history. We calculate a time-calibrated molecular phylogeny and use it to reconstruct the historical biogeography of the Panorpodidae, in order to explore the family’s phylogenetic origin and the biogeographical process that resulted in the present disjunct distribution.

Location: Eastern Asia and North America.

Methods: Sequence data from mitochondrial (COI and COII) and nuclear DNA (28S and EF-1a) were assembled from eight ingroup species. A phylogeny was reconstructed using maximum-likelihood analysis and Bayesian inference, and divergence times were estimated using fossil-calibrated Bayesian analysis. Ancestral areas were reconstructed with rasp 3.02, implementing dispersal–vicariance analysis, dispersal–extinction–cladogenesis and Bayesian binary MCMC.

Results: The initial diversification of Panorpodidae occurred during the Ypresian (c. 53.9 Ma). A wide ancestral distribution in eastern Asia and western North America was inferred from the biogeographical analyses. The original range of Panorpodes across eastern Asia and western North America was fragmented by intercontinental vicariance. The genus Brachypanorpa was initially restricted to western North America and subsequently dispersed into eastern regions of North America.

Main conclusions: Two alternative biogeographical patterns were recovered. Either Panorpodidae was restricted to western North America in the Eocene and subsequently dispersed into eastern Asia or–more reasonably–it was widely distributed in western North America, eastern Asia and Europe during the Eocene. Our biogeographical reconstructions corroborate the significant role of vicariance in shaping the current eastern Asian and North American disjunction in Panorpodes. The geographical separation of western and eastern North American Brachypanorpa species is likely to have resulted from the uplift of the Rocky Mountains and the emergence of grassland biomes in central North America.