AlphaI domain integrins have been found in the ascidian Ciona intestinalis. We produced Ciona alpha1I domain as a recombinant protein. It did not recognize fibril-forming collagens or bind to GFOGER or other similar motifs in triple-helical peptides. No GFOGER motifs were found in Ciona collagens. As Ciona alpha1I bound to collagen IX, we propose that before the emergence of GFOGER-dependent collagen receptors in vertebrates, alphaI domain integrins might have been able to bind to collagen with alternative mechanisms.