Unformatted text preview: first evolved in fish . • Oreochima & similar pholidophorids (late Triassic) -- The most primitive teleosts, with lighter scales (almost cycloid), partially ossified vertebrae, more advanced cheeks & jaws. • Leptolepis & similar leptolepids (Jurassic) -- More advanced with fully ossified vertebrae & cycloid scales. The Jurassic leptolepids radiated into the modern teleosts (the massive, successful group of fishes that are almost totally dominant today). Lung transformed into swim bladder. Eels & sardines date from the late Jurassic, salmonids from the Paleocene & Eocene, carp from the Cretaceous, and the great group of spiny teleosts from the Eocene. The first members of many of these families are known and are in the leptolepid family (note the inherent classification problem!)....
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- Spring '10
- Geology, Actinopterygii, Jurassic, primitive jawless fish