I was reviewing a manuscript that describes a new species and erects a new genus based on this new species. I disagreed with the creation of a new genus in that manuscript because I think it failed to present valid supporting characters and has fallen into the 'autapomorphy trap'. This term refers to the phenomenon that a higher-level taxon (i.e, above species) is created solely based on unique, autapomorphic characters. A well-known example is the class Aves. Birds have been given a equivalent rank, ie. cass, as the paraphyletic assemblage 'reptiles', primarily on the basis of their highly modified morphology and ecology (wings and aerial flight). However, birds are nothing more than 'derived' reptiles. They have all the characters that define reptiles, although some in highly modified manner. Similar cases, albeit unfamiliar to most readers, can be seen in the world of insect taxonomy. In the manuscript I was reviewing, the new genus is based on unique or strange characters such as expanded pronotal lobe, large protrusion on the pygophore and short phallothecal sclerite. These characters cannot tell the relationship between this proposed new genus and other existing genera. The proposed new genus clearly possess all the characters that would probably define an existing genus, Zelus. Therefore, I see no good reasons to not place this new species under Zelus. There may be some contention over the actual generic limit of Zelus, which, I don't think will support the erection of a new genus (although it would support not really the placement under Zelus either).
In my research project, I have an example of problematic taxonomy attributed to the autapomorphy trap as well. I did not create it, though. The tribe Rhaphidosomini have very slender body, giving them an appearance almost indistinguishable from stick insects. This is also the basis for having this group as a tribe and separating them from another tribe, Harpactorini. My research shows that the Rhaphidosomini are nested within the Harpactorini on a phylogenetic tree and are nothing more than 'derived' and highly modified harpactorines. The Rhaphidosomini-Harpactorini relationship would be similar to the birds-reptiles relationship.
I can see this prevalence of this problem in the taxonomic literature of Heteroptera, recent or historical and my guess is that it is probably quite common in the taxonomy of other groups of insects too.
The falling into the autapomorphic trap by taxonomists nowadays (we are not talking about pre-Hennigian 1950s or 60s) manifests the continued lack of rigorous phylogenetic analyses in many taxa and the lack of penetration of cladistic consciousness in practicing insect taxonomists. The corollaries of these problems go beyond the autapomorphy trap and include several other bad taxonomic practices. I think this cladistic-taxonomic gap should be reviewed and addressed. Anybody interested in this topic please contact me for a small collaborative project.
You can also read an article below that discusses some mistakes commonly made in doing taxonomy.
Writings related to insects, biodiversity and science in general