Final answer:
Paranthropus boisei is the likeliest genus and species of the discovered fossil with hyper-robust facial features in a strata dating to approximately 1.8 million years ago.
Step-by-step explanation:
The likeliest genus and species of the discovered fossil with hyper-robust facial features in a strata dating to approximately 1.8 million years ago would be Paranthropus boisei.
Paranthropus boisei, also known as the hyper-robust hominin, had a flat face, large jaws, and large attachment sites over the entire skull for chewing muscles. It had a robust build and its molars showed heavy wear, indicating a coarse and fibrous vegetarian diet.
Therefore, based on the description of the fossil, Paranthropus boisei is the most likely genus and species.