Synonymy, the word used to describe the situation where a biological species has more than one name, is confusingly complex. This fact is often not properly appreciated even by expert systematists who, whilst excellent at species distinction or recognition appear far less clear about names and hide behind phrases such as sensu aucttorum, sensu Brit. Aucct. and so on. Various punctuations, also, may be significant though often only to the author who may in any event be in error or copying previous error.

True synonymy is where one author has described a species unaware that this has already been done or believing his biological species to be different (a view not shared by the author of the synonymy). The first situation is very common with authors of the nineteenth century when a rush to describe species coincided with wars and revolutions which impeded travel and delayed book delivery. Nationalism and language difficulties were other problems. The second, called 'splitting' common in certain groups (the Lepidoptera, for instance) in the past is prevalent today. Unfortunately the inclusion of the authors name as part of the name has encouraged glory seekers.

Misidentifications are also included in synonymies. This is unfortunate since the two are not really the same. Here a later author has misunderstood a previous author's diagnosis and therefore misapplied the previous author's name. The error, if the later author produced an excellent and therefore popular book, particularly one with a much better description of the biological species in question, is often perpetuated though sometimes only in one country.

Synonymies are often spuriously impressive with lots of Latin and book titles. However , asked to explain the situation the author is at a loss and many situations are simply guesswork. Beware of those where the author of the synomym decision is not given.