Science news this week: An enigmatic human relative, dark matter discovery and mysterious lights in the sky during nuclear weapons tests Live ScienceEarly hominin Australopithecus afarensis may not be our human ancestor after all Natural History MuseumMystery foot suggests a second early human relative lived alongside Lucy NBC NewsNew finds shed light on diet and locomotion in Australopithecus deyiremeda NatureTwo Australopithecus Species Co-Existed in Ethiopia 3.4 Million Years Ago Sci.News