Sacabambaspis

Sacabambaspis is an extinct genus of jawless fish that lived during the Ordovician period, around 460 million years ago. Known from fossil discoveries primarily in South America, particularly in Bolivia and Argentina, Sacabambaspis is one of the earliest known vertebrates. It had a distinctive flattened, tadpole-like body and a head shield made of bony plates, which offered protection and may have helped with hydrodynamics. Unlike modern fish, it lacked jaws and instead had a mouth adapted for filter-feeding or scraping food from surfaces. Sacabambaspis provides valuable insight into the early evolution of vertebrates, showcasing primitive features that hint at the ancestral traits of later jawed fish.