Lungfish Phylogeny
Jarvik also studied the anatomy and relationships of lungfish which he held to be relatively primitive gnathostomes, possibly related to holocephalans, and of acanthodians, which he considered to be elasmobranchs rather than osteichthyans. He made contributions to a number of classical problems in comparative anatomy, including the origin of the vertebrates the origin of the pectoral and pelvic girdles and paired fins, and the homologies of the frontal and parietal bones in fishes and tetrapods
Finally, Jarvik investigated the anatomy of Ichthyostega, resulting in a monograph with an extensive photographic documentation of the material collected in 1929-1955.
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