marcverhaegen

Thanks for discussing this. Unfortunately, there are still a lot of misconceptions & unproven assumptions about our semi-aquatic evolution (so-called AAT or AAH) not only by AAT opponents, but also by some proponents. Our semi-aquatic phase didn’t happen 6 or more mill.yrs ago as Elaine Morgan thought (Hardy even thought >10 Ma), it has nothing to do with apes or australopiths, but it is about archaic Homo during the Ice Ages (Pleistocene 2.5 - 0.01 Ma). Most erectus fossils are typically found amid edible shellfish (marine & freshwater) and show several unmistakable convergences to littoral species: pachyostosis (thick & dense bones), platymeria (flattened femora), platycephaly (long low flat skulls), ear exostoses (as in human divers), orbital rim (eye-protecting), intercontinental dispersal (as when fossil whales became littoral), projecting nostrils etc. Pleistocene Homo did not run over open plains, but simply followed the African & Eurasian coasts & rivers, where they beach-combed, dived & waded bipedally for littoral, shallow aquatic & waterside foods. Our "scars of evolution" (title of one of Elaine's books) show that our ancestors' lifestyle at some time(s) included shallow frequent diving for shellfish, probably this was early-Pleistocene, when they followed the coasts: 1.8-Ma Homo fossils are found as far as Mojokerto on Java (in deltaic sediments, amid shellfish & barnacles), Turkana in the Rift (where H.erectus appeared together with stingrays, showing a marine connection then) & Dmanisi in Georgia (at a confluence of big rivers not far from the Black-Caspian Sea connection then). This littoral diaspora has been called the “coastal dispersal” model by Stephen Munro (Molluscs as Ecological Indicators in Palaeoanthropological Contexts 2010 PhD thesis Austr.Nat.Univ.Canberra), IMO a much better term than “aquatic ape”, see my paper attached. Please also google the recent papers of José Joordens & Stephen Munro http://www.smh.com.au/technology/sci-tech/anu-archaeologist-helps-discover-earliest-human-engravings-20141203-11ys3h.html In any case, our Pleistocene ancestors did not run over savannas as popular views still assume: this is biologically & physiologically, see e.g. my letter to Nature 325:305-6 in 1987, Origin of hominid bipedalism: "... Man is the opposite of a savanna inhabitant. Humans have thermo-insulative subcutaneous fat layers, which are never seen in savanna mammals. We have a water- and sodium-wasting cooling system of abundant sweat glands, totally unfit for a dry environment. Our maximal urine concentration is much too low for a savanna-dwelling mammal. We need much more water than other primates, and have to drink more often than savanna inhabitants, yet we cannot drink large quantities at a time ..." Humans have about 10 times as much SC fat as chimps, which is a serious risk of overheating in an open milieu. And salt & water are scarce on savannas: sweating is a very poor solution in open environments, but overheated furseals on land also sweat profusely through abundant sweat glands on their naked hind-flippers. HE'13.pdf