Three Into One Will Go

摘要

One corner of the world of ichthyology has just become a little tidier. Writing in Biology Letters, Johnson et al.' report their investigations of representatives of three families of marine fish - which, they find, are in fact the larvae, males and females of a single family. The previous tripartite designation was understandable, however. Johnson and colleagues reveal that the larvae undergo extraordinary metamorphoses, through post-larval and juvenile stages, before becoming transformed into male and female adults that are themselves wondrously different in appearance and anatomy. The fish concerned are the tape-tails, bignose fishes and whalefishes, which respectively are currently assigned to the families Mirapin-nidae, Megalomycteridae and Cetomimidae. Johnson et al. have explored the possibility that the mirapinnids and megalomycterids are in fact pre-juvenile and adult male cetomimids, respectively. Their investigations involved study of fresh megalomycterids netted at depth in the Gulf of Mexico, as well as of museum holotypes of various forms, and molecular analyses of mitochondrial DNA (a holotype, or type specimen, is the original specimen from which the description of a new taxonomic group is made).