petromyzon

Petromyzon is a genus of jawless fish belonging to the family Petromyzontidae, commonly known as lampreys. The genus name "Petromyzon" is derived from the Greek words "petra" (stone) and "myzo" (to suck), referring to their distinctive mouthparts. Species within this genus are characterized by their elongated, eel-like bodies, lacking paired fins and scales. They possess a horny, circular mouth with sharp, horny teeth, which they use to attach to host fish and feed on their blood and tissues.

The life cycle of Petromyzon species typically involves an aquatic larval stage, known as an ammocoete, which is a filter feeder. After a period of development, the ammocoetes metamorphose into their adult form. Many species are anadromous, meaning they migrate from saltwater to freshwater to spawn, while others remain entirely in freshwater. Adult lampreys, particularly the parasitic species, are known for their impact on fish populations, especially in areas where they are introduced and are not native. Non-parasitic species, on the other hand, typically do not feed as adults and focus on reproduction. The genus Petromyzon includes a few recognized species, with Petromyzon marinus, the sea lamprey, being one of the most widely known and studied due to its invasive status in the Great Lakes.