“This review focuses on novel hypotheses of animal phylogeny and the degree of support for them.”

This paper is a much-needed comprehensive review of animal phylogeny. Although the paper addresses several types of data, it differs from previous works by embracing discoveries made with molecular data. As such, it summarizes many other highly important papers in the field and provides interpretations of controversial topics making animal phylogenetics more accessible to researchers in other disciplines. Because comparative biology relies on understanding evolutionary relationships, the topic is of interest to a wide variety of scientists.

This review focuses on novel hypotheses of animal phylogeny and the degree of support for them. Perhaps one of the more useful attributes of the paper is that it points to underdeveloped areas of research and unresolved issues that need more attention. Thus, in addition to being a review, I hope that it stimulates research by making researchers aware of some of the outstanding questions.

Since the late 1980s, our understanding of the relationships of major animal lineages has been rapidly changing. The pace and nature of some of these discoveries has been such that many researchers not directly involved in such studies have had difficulty keeping up with the field.

However, in the past several years, our understanding of animal relationships has improved considerably. We have been able to determine relationships among many major lineages of animals. Also, we know which taxa deserve more effort. The paper is significant because it provides a comparative framework of animal relationships for researchers in a variety of disciplines.

This line of research originally started as part of my Ph.D. dissertation in the early to mid 1990s. The main issue for me has been continuing the work through different academic appointments. I was fortunate enough to have postdoctoral advisors that were supportive, and was able to more fully develop my program once I had a tenure-tract position. Another issue was finding a venue and editors receptive to such a review.

The social and political implications of this work are less direct. However, it does provide an example of how evolutionary research proceeds. The fact that hypotheses are made, tested, and, ultimately, refuted or accepted, is critical to how we advance knowledge.

It illustrates that, although our view of how evolution proceeds can change, we nonetheless accept that evolutionary forces are the causative agent of generating the wonderful diversity of life around us.