Indian monsoon drove the dispersal of the thoracica group of Scytodes spitting spiders.

Abstract

We examined the global biogeography of the Scytodes thoracica group of spitting spiders based on 23 years of sampling at the species level (61 species in the thoracica group and 84 species of Scytodes) using DNA data from six loci. Our results indicated that the thoracica group initially dispersed from Southeast Asia to East Africa between 46.5 and 33.0 million years ago, and dispersal events intensified between Southeast/South Asia and East/South Africa from the early to late Miocene. The timing of these events indicates that Asian-African faunal exchange of the thoracica group was driven by the Indian monsoon, and the pattern of dispersal suggests that colonialization took root when the Indian monsoon shifted from a North-South direction to an East-West direction from the middle Eocene.