be ancestral to the other two species, or closely related to the ancestor. Proponents of paraphyly allocate these three species to the genus Australopithecus as A. boisei, A. aethiopicus, and A. robustus. British geologist Bernard Wood and American palaeoanthropologist William Kimbel are major proponents of monophyly, and against include Walker. This species, originally named Paraustralopithecus aethiopicus, cannot retain the species epithet aethiopicus if moved to genus Australopithecus because Australopithecus aethiopicus is already a junior synonym of Australopithecus afarensis. Such a classification would have to use the name Australopithecus walkeri for this species. The change of species epithet would also happen in a taxonomy that classifies all hominins as Homo. Description Typical of Paranthropus, KNM WT 17000 is heavily built, and the palate and base of the skull are about the same size as the P. boisei holotype OH 5. The brain volume of KNM WT 17000 was estimated to have been , which is smaller than that of other Paranthropus. The combination of a tall face, thick palate, and small braincase caused a highly defined sagittal crest on the midline of the skull. The only complete tooth crown of the specimen is the right third premolar, whose dimensions are well above the range of variation for P. robustus and on the upper end for P. boisei. Unlike other Paranthropus, KNM WT 17000 did not have a flat face, and the jaw jutted out (prognathism). In regard to the temporal bone, KNM WT 17000 differs from other Paranthropus in that the squamous part of temporal bone is extensively pneumaticised, the tympanic part of the temporal bone is not as vertically orientated, the base of the skull is weakly flexed, the postglenoid process is completely anterior to (in front of) the tympanic, the tympanic is somewhat tubular, and the articular tubercle is weak. Like P. boisei, the foramen magnum where the skull connects to the spine is heart-shaped. The temporalis muscle was probably not directed as forward as it was in P. boisei, meaning the P. aethiopicus jaw likely processed food with the incisors before using the cheek teeth. The incisors of P. boisei are thought to have not been involved in processing food. The long distance between the first molar and the jaw hinge would suggest KNM WT 17000 had an exceptionally long ramus of the mandible (connecting the lower jaw to the skull), though the hinge's location indicates the ramus