RMRGEXGW–. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. ACTINOPTERYGIAN INTERRELATIONSHIPS • Lduder (liul LieiU 159. Figure 45. Jaw protrusion in the percoid fish Monocirrhus during the capture of prey. A-D. Four representative stages of mouth opening and jaw protrusion. D. fully protruded condition. (From Liem, 1970.) Atherinomorplia This group is first known from the Eocene and according to the most recent classification (Parenti, 1981; Rosen and Parenti, 1981) contains 11 families and about 830 species, including the killifish- es (cyprinodontids), live-bearing top minn