Estimating time and space in the evolution of the Lepidoptera

Estimating time and space of events in the evolution of life has been an important issue ever since the acceptance of the concept of evolution. A fair idea of these events is crucial in understanding how the evolution of a group of organisms has been shaped not only by intrinsic factors (mutation, population growth, food preference, etc.), but by extrinsic, environmental factors as well. Initially, and for a very long time, fossils formed the only clue to what had happened in deep history. Although the first fossil lepidopteron was described well before the idea of evolution had clearly been formulated (Charpentier 1843; described as Sphinx atava [Sphingidae], moved to Nymphalidae by later authors), fossil Lepidoptera remained too rare to play an important role in elucidating the evolutionary history of the Lepidoptera, both in time and space. Every attempt to estimate the origin of the Lepidoptera from fossils had to extrapolate the data to far back in history and to make use of (reputed) circumstantial evidence. Thus, Forbes (1932), starting from a well preserved butterfly fossil (Prodryas persephone Scudder, 1878, about 20 Ma old), concluded that “there is a slight weight of probability that the Lepidoptera arose in the late Carboniferous or early Permian period ...” (i.e. some 280–300 million years ago). Not only fossils, also the study of recent taxa led some authors to unwarranted extrapolations and speculations on the origin of higher taxa. In a study of American Copper butterflies (Lycaeninae) Miller & Brown (1979) speculated that the basal split in the Lycaeninae took place over 100 million years ago and, thus, the origin of the “Lycaenoid root” should be placed much further back into the Mesozoic. More generally, Brown (1987), while discussing the evolution of Neotropical butterflies, suggested that pantropical groups at the level of subfamily and Estimating time and space in the evolution of the Lepidoptera