More assassins on the radar: As many as 24 new species of assassin bugs described

Assassin bugs are insects that prey upon other small creatures, an intriguing behavior that gives the common name of their group. There are some 7000 described species of assassin bugs, but new species are still being discovered and described every year.

The new species described by scientists Drs Guanyang Zhang, University of California, Riverside, and Arizona State University, Elwood R. Hart, Iowa State University, and Christiane Weirauch, University of California, Riverside, belong to the assassin bug genus Zelus.

Linnaeus, the Swedish scientist, who established the universally used Linnean classification system, described the first species (Zelus longipes) of Zelus in 1767. Back then, he placed it in the genus Cimex, from where it was subsequently moved to Zelus. All of Zhang & Hart's new species are from the Americas. Mexico, Panama, Peru, Colombia and Brazil are some of the top countries harboring new species.

To conduct the research, Zhang examined more than 10,000 specimens and nearly all of them have been databased. These specimen records are now freely and permanently available to everybody. Zhang's work demonstrates the value of natural history collections. The specimens used in his work come from 26 museums in nine countries. The discovery of the new species would not have been possible without these museums actively collecting and maintaining their insect collections.

It took more than a century for some of the new species to be formally recognized and described. The first specimens of the species Zelus panamensis and Zelus xouthos, for example, had been collected in 1911 and 1915 from Panama and Guatemala. However, since then they had been waiting quietly in the collection of the Smithsonian National Museum of Natural History, USA. Now, over 100 years later, they are finally discovered and given scientific names.

Meanwhile, more recently collected specimens also turned out to be new species. Specimens of Zelus lewisi and Zelus rosulentus were collected in 1995 and 1996 from Costa Rica and Ecuador, about two decades ago, a timeframe considered relatively short for taxonomic research. These interesting patterns of time lapse between specimen collecting and scientific description suggest that it is equally important to examine both long deposited in museums specimens and those newly collected from the field.

The kind of research performed by Zhang and his colleagues is called revisionary taxonomy. In revisionary taxonomy a researcher examines a large number of specimens of a group of organisms of his or her interest. This can be either a monophyletic lineage or organisms from a particular region. The scientist's goal is to discover and describe new species, but also examine and revise previously published species.

Besides describing new species, the present taxonomic monograph treats another 47 previously described species. Nearly all species now have images of both males and females and illustrations of male genitalia. Some of these insects are strikingly brightly colored and some mimic wasps.