Final answer:
The Taung child provided evidence that important hominin traits such as canine reduction and bipedalism predated the expansion of brain size. Brain size alone is not the defining feature of hominins as tool use and bipedalism are also key indicators.
Step-by-step explanation:
The Taung child implied the opposite scenario of Piltdown: Canine reduction occurred before brain size expansion. Bipedalism developed before brain expansion. Brain size is not the defining feature of hominins; it's either bipedalism or tool use.
The findings from different hominin species such as Homo naledi and H. floresiensis, which both possessed small brains, support the scenario where other traits like bipedalism and tool use, rather than large brain size, signify the emergence of hominins. The research into Homo habilis and other hominin fossils by paleoanthropologists like the Leakeys and Napier indicates that complex criteria beyond just brain size, such as the ability to walk on two feet, should be considered when classifying species under the genus Homo.
Notable hominin characteristics include cranial capacity, tool use, reduced prognathism, and the anatomical features suited for bipedalism. Research demonstrates that hominins evolved a variety of adaptive traits beyond just increased brain size, with the use of tools and bipedal locomotion being integral to their development in our evolutionary history.