Homo megaptera; Whale-sized merpeople first developed in 7020 AT. This clade was the result of a program of gengineering in the Zennor system in Libra, a system which contains several waterworlds. Megapteras have spread widely across the Terragen Sphere since this time, and are now found on numerous panthallasic worlds and gaian planets with oceans and seas.
Megapteras generally have very good relations with provolved dolphins and sapient whale clades, but this is not always the case; they have very different psychological characteristics to most of the older water-dwelling clades, and sometimes come into conflict with them.
Homo Megaptera are almost exclusively water-breathers, although some subclades can breathe oxygenated air as well, and others use hi-tech breathing equipment when interacting with surface-dwellers. They have powerful arms, a whale-like tail but no legs. They can dive as deep as 7km searching for squid and krill, although Megas on Zennor in the current era usually eat geneered meat-kelp.
Their gills are located beneath the powerful wing-like arms, which have individual digits but poor manipulative skills. Most populations make use of hand-tech robots for fine work.