SPECIES, STASIS, AND STRATIGRAPHY: GETTING IT WRONG FOR THE RIGHT REASON

In 1954 Peter Sylvester-Bradley convened in London for the Systematics Association a symposium on The Species Concept in Palaeontology. The slim volume of papers published in 1956 provides a remarkable historical window into the status of the paleontology of the time. Most paleontologists in those days were biostratigraphers, and the group Sylvester-Bradley assembled was certainly dominated by them. Those were heady years for our science as paleontologists strove to accommodate the needs, not always compatible, of stratigraphy and the new systematics. The scene was complicated by Darwin’s expectation of gradualism in the fossil record, by new evolutionary inklings stemming from a few studies, and by an unrealistic view of the promise of the genetics of the times as a key to successful systematics—a promise that is coming only now to fruition.

By the late 1960s the view was held widely that paleontology was rich in data and poor in ideas. In the 1950s, however, the opposite was true. Participants in the symposium relied repeatedly on a few thorough paleobiological studies; paid homage to statistics as the pathway into the future (Remember the 75 percent rule?); or presented graphs of hypothetical species and populations evolving gradually through time—almost always without any empirical studies to fortify their views or, if real fossils were mentioned, falling back on Gryphaea.

With no concept of punctuation or stasis to guide them, these biostratigraphers, one after the other, denied what their data had been telling them since the days of d’Orbigny as they tried to come to grips with three species concepts: biological species, morphological species, and that chimera—the chronospecies.