Passerinerines are small land birds with fragile bones. As a result they are rarely fossilized, giving few clues to their evolution. The Hirundinidae family, is the family name the Swallows belongs to, and is also part of the Passerines order. It was in this period that Laurasia and Gondwanaland fragmented. Pterodactyls and other small birds diversified at a fast pace during this time.
Archaeopteryx is the most primitive taxon.
The morphological evolution of the oscines is of a complex nature. Identification of this avian class of birds was difficult to determine. It was later discovered that the Passeriformes are divided into two groups, Tyranni for the sub oscines and Passeri for the oscines. Distribution The Bank Swallow is one of seventy-four species of swallows representing the Hirundinidae Family. The species includes both the swallow and the martin families and are found worldwide, except above the Arctic Circle, Antarctica and some remote islands.