Natural History Photographs


Some notes on my use of taxonomy

The pages on this site dedicated to animals, plants and fungi are organized systematically. In itself this is unremarkable, but the choice is far from innocuous. Modern classifications are in line with our knowledge about evolutionary relationships; but for many taxa, this knowledge still is in a state of flux, with major revisions frequently happening. This applies especially to groups for which morphological evidence is insufficient to arrive at a reliable phylogeny. For such groups, the recent developments in DNA sequencing technology have opened up a completely new window on the evolutionary relationships. As it takes a while before the dust thrown up by the new data will have settled, the classifications of these groups are still quite volatile. Thus, there is often more than one option to organize the material on this site.

In organizing my photos taxonomically, I thus have to make choices, choices that sooner or later may become outdated. For instance, insights into the phylogenetic relationships between digger wasps (Crabronidae) and bees (Apidae) have changed since I created the pages dedicated to them. Then, Crabronidae and Apidae where seen as sister groups; but by the insights of 2017, bees originate within the Crabronidae, making the latter group paraphyletic - a mortal sin in today's taxonomy. To correct that sin in my presentation, I will thus have to bring my presentation in line with current insights.

Even though I aim to present my material according to recent insights about phylogenenetic relationships, I do not always strictly adhere to this intention. There are two reasons to not always rely on the newest phylogeny, one practical and one more principled. The practical reason is that it may take quite some time to rework the organization of the presentation of a praticular group, depending on how large the revision is. I may choose not to prioritize such a revision if other changes are more pressing. The more principled reason is that when a well-established classification is to be overthrown, I prefer to base my presentation on the new concensus view; but such a view is not always available. If a consensus view isn't even remotely in sight, I prefer to stick to the outdated but well-established view, as I did for a long time for the Hymenoptera.

Till quite recently (say 2015), I used a variety of sources, often based on convenience. However, since different sources on the taxonomy of the same group are fairly often inconsistent, this lax approach is bound to create problems. Therefore, I recently adopted a more organized approach, keeping track of the sources I used for the organization of the pages. The list below documents the sources I used for the various groups. In view of my recent change in approach, this list is far from complete, and I will update it whenever I review and reorganize the presentation of a particular group.

References