show Abstracthide AbstractWe produced a chromosome-level genome assembly for the Gulf pipefish in order to better understand the evolution of derived and novel morphological traits. Syngnathid fishes, which include this particular species, are ideal study systems in this regard. Using the annotated genome, we explored potential genetic bases for several derived features of these fish, including an elongated body axis and snout, tooth loss, pelvic fin loss, and male pregnancy. We also examined structural chromosome evolution among teleosts, facilitated by our genetic-map-anchored assembly.