Historical patterns of avian taxonomy -- 2

Another plot shows different patterns in the data.
This plot show the Year of publication (y-axis) plotted against the linear taxonomic sequence (x-axis). Each point represents a currently valid taxon name distributed by taxonomic order (x-axis) and year (y-axis). It can be thought of as "date chromatography" such that the taxonomic arrangement is displayed by its date distribution.

Several interesting patterns are present here.

The importance of the ordering on the X-axis is relatively unimportant, though a few patterns result from it, and will be disucssed below.

The most striking feature is the apparent "gap" that is in the lower part of the plot. This "gap" starts at 1790, and extends to 1815. The apparent "floor" of the gap results from the large number of taxa described by Gmelin in 1788, 1789 (see plot #3 for a demonstration of this). If the Gmelin taxa (which are mostly Latham taxa that Gmelin applied binomena to) are removed, the "gap" blends in with the rest of the pre-1815 data.

The "ceiling" of the gap appears to be real, and is an interesting phenomenon. It starts with the large number of taxa described by Vieillot -- although he described a few taxa before this period of sustained intense activity occurred.

After it's sudden increase, this rate of activity continued largely without change; it is not the result of one individual's efforts. (As occured in the apparent "floor" of the gap.)

This "gap" does not seem to be present in the other taxonomic groups I have investigated so far, and that have enough data to reveal the presence of a possible "gap". (I have looked at mammals, fish, lichens, among others).

For a further discussion of this "gap" see plot #6 and accompaying text.

In the lower portion of the plot, three areas show a relative sparseness of points.

In the left middle, this area represents the hummingbrids - relatively underrepresented in early collected material.

The middle contains a similar area with paucity of points, this represents the New World Nine-primaried Oscines, especially Thamnophilids and Furnarids. I believe thier underrepresentation in early descriptions results from the fact that birds were not widely taken by early collectors, not recognized as distinct taxa by early taxonomists, or both.

The third region is the old world Sylviid warblers, underrepresented early on due to limited exploration in much of the remote Orient.

Comments&Suggestions to Data Steward

Alan P. Peterson, M.D.
POB 1999
Walla Walla, WA 99362-0999

Last updated 2000.04.24