JASs Invited Reviews Journal of Anthropological Sciences Vol. 97 (2019), pp. 1-24 the JASs is published by the Istituto Italiano di Antropologia www.isita-org.com Mosaic evolution in hominin phylogeny: meanings, implications, and explanations Andrea Parravicini 1 & Telmo Pievani 2 1) Department of Philosophy, State University of Milan and Department of Biology, University of Padua, Italy e-mail: andrea.parravicini@unimi.it 2) Department of Biology, University of Padua, Italy e-mail: dietelmo.pievani@unipd.it Summary - In paleoanthropological literature, the use of the term “mosaic” (mosaic evolution, mosaic trait, mosaic species, and so on) is becoming more and more frequent. In order to promote a clarifcation of the use of the concept in literature, we propose here a classifcation in three diferent meanings of the notion of mosaic in human evolution: 1) morphological (inter-specifc and intra-specifc) instability in a certain phase of a branched phylogeny; 2) multiple trajectories and versions of the same adaptive trait in a branched phylogeny; 3) the trait itself as a complex mosaic of sub-traits with diferent phylogenetic stories (as is the case in language). We argue that the relevance of such mosaic patterns needs a macro-evolutionary interpretation, which takes into consideration the interaction between general selective pressures (promoting diferent versions of the same adaptation) and a cladogenetic approach in which speciation played a crucial role, due to ecological instability, habitat fragmentation, and geographical dispersals in human evolution. Keywords - Mosaic evolution, Macro-evolutionary approach, Bipedalism, Encephalization, Symbolic behavior, Stone-tools, Human language evolution. The term “mosaic” in human evolution The leading perspective on human evolu- tion has been largely modified, due to a num- ber of different factors: the paleontological and archaeological record has been widely expanded; new dating methods and tools of integrated analysis are available; the possibility to integrate a great amount of new convergent evidence com- ing from different fields – such as paleontology, molecular biology, paleo-biogeography, paleo- ecology, social studies – is increasing more and more. All these changes and the dramatic expan- sion of the empirical basis have made it clear that the linear model of a single anagenetic evolution is today hardly tenable (despite its recent resur- gence for restricted periods of human evolution: see Lordkipanizde et al., 2013 and Rightmire et al., 2017, about an alleged single polymorphic species of early Homo). Today, the scientific com- munity is generally unanimous in replacing the old linear anagenetic model of human phylog- eny with the cladogenetic Darwinian model of a knotty and irregularly branched tree. However, the more new data and findings are available, the more the general picture of hominin phylogeny seems puzzling and problematic, which raises new research questions. Despite the fact many efforts have been made to put in order and explain the tangled puzzle of kinships and evolutionary trajectories, the pic- ture of the hominin tree remains full of question marks and blind spots, especially following dis- coveries in recent years. Ardipithecus ramidus has weakened the dominant framework of the 20 th century that used living African apes, especially chimpanzees, as proxies for the immediate ances- tors of the human clade. Referring to a “missing- link” between humans and such alleged apelike ancestors, after “Ardi”, no longer makes sense (White et al., 2015). A stone tool industry has been found at the Lomekwi 3 site, West Turkana (Kenya), at 3.3 Mya, predating the Oldowan by e-pub ahead of print doi 10.4436/jass.97001