Final answer:
Paranthropus robustus and Paranthropus boisei are species under the Paranthropus genus, which were muscular, early hominins with adaptations for a tough, plant-based diet, characterized by robust cranial features and large molars, not directly ancestral to modern humans.
Step-by-step explanation:
The names Paranthropus robustus and Paranthropus boisei refer to species classified under the genus Paranthropus, known for their robust cranial features and dentition adapted to a tough plant-based diet. These species existed approximately 2.5 million years ago. Paranthropus boisei, discovered by Louis and Mary Leakey in the Eastern Rift Valley over a span of 30 years, is recognized by a distinct sagittal crest along the skull's top for muscle attachment, known as the hyper-robust hominin. The name boisei was originated from Charles Boise, an early benefactor of their archaeological research. Paranthropus robustus was discovered slightly earlier, in 1938, by Robert Broom and featured similarly heavy jaw muscles, indicated by a flared zygomatic arch and large molars, suggesting a diet of hard nuts and seeds. Both species played an important role in paleoanthropology in understanding the diverse evolutionary pathways of hominins.