sailfish and spearfish are classified surface, and have elongated bills, flatfish in the family of Xiphidae and are the primarily live on the sea floor and are only species (Xiphias gladius) in this usually asymmetrical with their two eyes family. Though fossils of swordfish are located on the same side of their head. hard to come by, the oldest have been found in Italian rocks dating 15 million There is a saying that to know the future years around the same time billfish first one must first know the past because appeared, which like swordfish, have history has a knack for repeating itself. barely changed since they first evolved. This saying certainly rings true for the conservation of billfish. Like their living As mentioned before, it was long descendants, ancient billfish species believed that billfish and tuna evolved had long lifespans, grew to large sizes, from a common ancestor, but it was not and take much longer to reach sexual until further research conducted revealed maturity. These traits meant that when the the real story behind their evolution. rapid environmental changes occurred Recently, researchers have examined during the Cretaceous period, ancient the DNA from several species of billfish billfish and tuna species were unable and tuna including swordfish, striped to adapt quickly enough to survive. marlin, blue marlin, bigeye tuna, and For billfish and tuna swimming in our Top image, Jackfish. yellowfin tuna. DNA sequencing was oceans today, overfishing, pollution, and used to develop a genetic relationship climate change are rapidly altering our needlefish and sailfish. Unlike modern between billfish and tuna and the results marine environments. Fortunately, Homo billfish that are known to stun predators were quite surprising. Remarkably, the sapiens (humans) are capable of learning and prey alike with their bills, the small team found that tuna and billfish are only from history and are working to reverse Hemingwayids did not actively swim, distantly related. These results would these trends. Hopefully this article will and hunted their food in short bursts of imply that many of the adaptations encourage you to support conservation speed. From the Paleocene through the shared by tuna and billfish evolved efforts and help give billfish and tuna a Miocene (which ended 27 million years separately, a phenomenon known as better chance. ago), the world experienced remarkable convergent evolution. What’s more, the billfish diversity including the emergence authors found that billfishes are closely I hope this paper inspires dialogue of two ancestors (but now extinct) of related to flatfishes (Pleuronectiformes) about the often-overlooked evolutionary modern billfish families—the Blochiidae and jacks (Carangidae). This is an story of the billfish. I also hope that this and Xiphiorhynchinae. Unlike present astonishing result considering the dialogue will be incorporated in larger billfish (Istiophorids), their forebears differences in lifestyle, physiology and discussions about the conservation of possessed two bills of equal length—one morphology observed among these these charismatic sportfish. on the upper jaw and one on the lower fishes. While billfishes are extremely jaw. Swordfish however, unlike marlin, athletic, actively swimming near the

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