Biogeography of the Pepsis hymenaea-group: a new approach

The Pepsis hymenaea-group is basically defined by the reunion of the radial and costal veins at approximately a right angle, and by the 3-toothed male subgenital. Restricted to the northern and central Andes, the six species of this group occur between 500 and 3,000 altitudinal meters above the sea with very restricted distributional range. The actual argumentation on the diversification of the P. hymenaea-group is based on several processes of speciation and extinction as consequences of the climatic cycles. However, when we correlate species distribution with historic geological events from South America, the P. hemenaea-group diversification follows the Andean geomorphological evolution. Consequently, the ancestral population of P. hemenaea-group probably had a wider distribution in the actual region of the northern Central and Northern Andean Blocks, being separated by uplift these blocks. The ancestral populations that derived the three most basal species began to be isolated in the Miocene, with the uplift of the northern Central Andean Block. On the other hand, the ancestral populations that originated the three most apical species began to be isolated only in the Pliocene, when the Northern Andean Block started to uplift. Thus, the diversification of the P. hymenaea-group started about 23 million years ago, envolving several vicariant events.