BILLFISHES ARE CLOSELY RELATED TO FLATFISH

摘要

Scombroids are a collection of primarily predatory fish that include mackerels, tunas, bonitos and billfishes, found worldwide in tropical and temperate waters. Most scombroids are speedy swimmers, with a streamlined body shape as well as muscular, metabolic and cardiovascular features that allow them to swim continuously. They also have enhanced aerobic capabilities to power their athletic swimming. In addition, some scombroids, such as tuna and billfishes (e.g. marlin and swordfish) have a remarkable physiological adaptation known as regional endothermy, where they maintain regions of their body at an elevated temperature relative to their surroundings, allowing them to expand their geographical range. These unique characteristics suggest that tuna and billfishes share a close evolutionary history; however, the phylogenetic relationship between scombroids remains unresolved. Numerous morphological and molecular studies have been conducted to determine the relationships between scombroid family members, producing conflicting results. Chris Moyes and his colleagues from Queen's University in Canada sought to resolve the classification of scombroid fishes using DNA sequencing.