Long-time REEF supporters, Les and Keri Wilk of ReefNet, recently discovered and photographed a distinctively marked population of the Greenbanded Goby, Elacatinus multifasciatus, on the island of Utila, Honduras. The population was distinguished by a prominent red stripe across the cheek that is not found on other populations of Greenbanded Gobies, as well as more numerous green bars on the body. The Wilks contacted Dr. Benjamin Victor (coralreeffish.com), a reef fish taxonomic expert, who conducted a regional genetic comparison of Greenbanded Gobies to evaluate hidden diversity within this colorful reef fish. As part of the study, the REEF database was used to document the current geographic range of the species. Dr. Victor's results identified the unique looking fish to be a separate species that is now called the Redcheek Goby (E. rubrigenis). He also discovered that, based on genetic results, Greenbanded Goby along coastal Panama, despite looking just like others in the species complex (i.e. a cryptic species, distinguished mainly by differing DNA sequences), are a distinct species that will now be called Panamanian Greenbanded Goby (E. panamensis). The study was published last month in the Journal of the Ocean Science Foundation.
The new species, the Redcheek Goby, replaces the Greenbanded Goby on the island of Utila and has not been sighted at any other location, potentially one of the smallest ranges reported for a Caribbean reef fish. With few exceptions, coral reef fishes have pelagic larvae that spend weeks to months developing in off-reef waters. As a result of this high dispersal ability, most Western Atlantic reef fish species have geographic ranges throughout the Caribbean Sea and adjacent areas. Endemic marine species (those only found in a given region or location and nowhere else in the world) are generally uncommon in the western Atlantic region. Furthermore, many of these widespread species show little, if any, variation in their genetic patterns between areas, particularly within the bounds of the Caribbean Sea with its many stepping-stone islands. Nevertheless, some groups of fishes, presumably those with more-restricted larval dispersal and strong local selection, show interesting patterns of endemism, genetic structure, and cryptic speciation within the region, for example among the Elacatinus cleaning gobies (e.g. Sharknose, Cleaning, Neon, Yellowline, etc.). Those reef fish taxa that contain cryptic species can provide valuable insights into the processes of speciation and the biogeographic history of the region, but also seriously challenge the traditional species concept. The results of Benjamin Victor's study highlight these challenges.
REEF is proud to be able to contribute to scientific studies such as this one. We are also thrilled that fishwatching by amateur non-scientists like our Fish Survey Project volunteers has been elevated beyond just a hobby, and is increasing the state of knowledge about reef fish diversity. The full citation of the publication is: Victor, B.C. 2010. The Redcheek Paradox: the mismatch between genetic and phenotypic divergence among deeply divided mtDNA lineages in a coral-reef goby, with the description of two new cryptic species from the Caribbean Sea. The Journal of the Ocean Science Foundation, Vol 3. It is freely available online here. To find out more about this and other scientific publications that have featured REEF data, visit our Publications page here.