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Herpetichthyes, Amphibioidei, Choanichthyes or Sarcopterygii?

1955; Nature Portfolio; Volume: 176; Issue: 4472 Linguagem: Inglês

10.1038/176126a0

1476-4687

Alfred Sherwood Romer,

Fish biology, ecology, and behavior

DURING recent decades, our ideas on the classification of fishes have changed greatly. In the early years of the century, it was believed that among the higher bony fishes (Osteichthyes), the ray-finned forms and crossopterygians were closely allied, and that the lungfishes were remote from the two, representing a presumably primitive if aberrant group. As an expression of such beliefs may be cited Goodrich's work on fishes in the Lankester “Treatise on Zoology”1, in which the Osteichthyes are divided into two subclasses, one for the Dipnoi alone, the other, the Teleostomi, including both Crossopterygii and the Actinopterygii. In succeeding decades, however, a radical change of opinion occurred. Principally due to the work of Goodrich himself and of Gregory and Watson, it became clear that the primary dichotomy of the Osteichthyes was of another sort, one major subdivision including the Actinopterygii alone, the other both Crossopterygii and Dipnoi. Huxley, in 18802, coined the name Herpetichthyes to describe the sub-tetrapod evolutionary stage represented by Ceratodus, and Smith Woodward, in 19313, suggested the expansion of the term to include (contra Huxley) the crossopterygians. Hubbs, in 19194, proposed Amphibioidei for Dipnoi plus Crossopterygii, and other writers have suggested an expansion of Crossopterygii to include the Dipnoi as well. Säve-Söderbergh, in 19345, in an unorthodox essay in classification, proposed a major subdivision of the vertebrates, including all the tetrapod classes plus the two fish groups concerned, to be named the Choanata, in reference to the presence of internal nostrils. I have (like others) rejected this classification, but in 19376 suggested that Choanichthyes would be appropriate as a designation for the included fish groups. None of the three terms previously suggested has met with any marked degree of acceptance; Choanichthyes has been adopted by a number of recent writers.