Homo floresiensis and Homo luzonensis are not temporally exceptional relative to Homo erectus

Abstract

ABSTRACTThe presence ofHomo floresiensisandHomo luzonensisin southeast Asia 90,000 to 60,000 years ago is considered surprising by many, and has been used to support their designation as unique species and the islands they were discovered on as refugia. Here, we statistically test the null hypothesis thatH. floresiensisandH.luzonensisrepresent temporally uninterrupted occurrences relative toHomo erectus. We do this using the ‘surprise test’ for the exceptionality of a new record. Results demonstrate thatH. floresiensisandH. luzonensisare not temporally distinct relative toH. erectus. Their late persistence should, therefore, not be considered surprising, they cannot reliably be inferred to be outside ofH. erectus’ temporal range, and – temporally – the islands of Luzon and Flores are not supported as refugia. Similarly, lateH. erectusat Ngandong, Java, is not demonstrated to be temporally distinct relative to earlier, principally mainland‐Asian,H. erectus. Further, we demonstrate that substantial numbers of fossil discoveries would be needed beforeH. floresiensisandH. luzonensisare outside ofH. erectus’expected temporal range. IfH. floresiensisandH. luzonensisare descended fromH. erectuspopulations, our results point toward either geographic processes of allopatric speciation or behavioural processes leading to a sympatric speciation event.